I found it quite annoying that the system would reboot every time I needed to start my truck.

All you need to do is add a fused 12 volt wire from your "True Ignition" circuit from you ignition harness WITH a diode, right into the red switched wire on the head unit. Have the band of the diode going towards the head unit - VELLA !!

The diode blocks the 12 volts from feeding back into the Ignitoin circuit, when you have your key in the Accessory posistion. You should be able to find them at Radio Shack of maybe a car audio shop will give you one!

True Igniton = 12 volts does not drop out during the start cycle.

Vella?

Vella?

I think he meant fromage -> http://www.vellacheese.com/

His french is a little rusty!

Mmmm j'aime la fromage mais il y a beaucoup de gras

I found it quite annoying that the system would reboot every time I needed to start my truck.

 

All you need to do is add a fused 12 volt wire from your "True Ignition" circuit from you ignition harness WITH a diode, right into the red switched wire on the head unit. Have the band of the diode going towards the head unit - VELLA !!

 

The diode blocks the 12 volts from feeding back into the Ignitoin circuit, when you have your key in the Accessory posistion. You should be able to find them at Radio Shack of maybe a car audio shop will give you one!

 

True Igniton = 12 volts does not drop out during the start cycle.

What problem were you having and what were you trying to fix exactly?

Were you on accessory power and then started the truck...it reboots?

Or is it rebooting when you turn your truck off and leave the key in the accessory position?

Or both?

I'm just trying to get a better feel for what you were trying to accomplish...and if it's the same for every car, because my car stock doesn't shut the radio off when I turn my car off, making this a pointless mod for me (and maybe others out there)

He's talking about running the radio from the accessory power, and then starting the truck. The radio will reboot every time. To go from a running engine to accessory power won't turn the radio off on any car as far as I know. The mod is to keep the radio from power cycling when you go from ACC to ON.

He's talking about running the radio from the accessory power, and then starting the truck. The radio will reboot every time. To go from a running engine to accessory power won't turn the radio off on any car as far as I know. The mod is to keep the radio from power cycling when you go from ACC to ON.

Yeah, that is very annoying. Sometimes. like when adding gasoline, I pull up to the pump and want to leave the audio playing (especially while streaming over BT). So I shut-down the engine and leave the key in the Accessory position. But when I restart the engine - the AVIC reboots. A very annoying side-effect of this is that it seems to wipe-out the iPod VR catalog. It has to do a full rebuild afterwards - takes several minutes instead of a few seconds like a reboot from a power-off condition.

I expect the poster's mod would be very vehicle specific. I had thought of doing something similar, but I wasn't sure if the power drop causing the reboot was from the Red (switched) or Yellow (constant +12V) feeds. I also wasn't sure it it was just caused by a voltage drop while cranking the starter, or if it was an intentional safety feature to keep the voltage drop from damaging accessories. The Z1x00 manual says the power source required is 10.8 - 15.1V DC, and I wouldn't be supprised if the car's battery dropped lower than 10.8 due to the high amperage draw when the starter cranks.

Since the posters mod just ensures that the red circuit is continuous when the ignition is on, it seems that on his vehicle at least, the voltage stays within range.

The vehicle specific trick is to find the correct circuit (that is, a circuit that is energized when the ignition is on but off when it is not). Modern cars often have this stuff computer controlled and the correct circuit might be harder to access/locate. On some engine it might be easy to just use the circuit that feeds the coil. But that might be hard to locate on some cars with solid state ignition.

So, poster, please give us more detail or suggestions on the best place to tap.

Yeah, that is very annoying. Sometimes. like when adding gasoline, I pull up to the pump and want to leave the audio playing (especially while streaming over BT). So I shut-down the engine and leave the key in the Accessory position. But when I restart the engine - the AVIC reboots. A very annoying side-effect of this is that it seems to wipe-out the iPod VR catalog. It has to do a full rebuild afterwards - takes several minutes instead of a few seconds like a reboot from a power-off condition.

 

I expect the poster's mod would be very vehicle specific. I had thought of doing something similar, but I wasn't sure if the power drop causing the reboot was from the Red (switched) or Yellow (constant +12V) feeds. I also wasn't sure it it was just caused by a voltage drop while cranking the starter, or if it was an intentional safety feature to keep the voltage drop from damaging accessories. The Z1x00 manual says the power source required is 10.8 - 15.1V DC, and I wouldn't be supprised if the car's battery dropped lower than 10.8 due to the high amperage draw when the starter cranks.

 

Since the posters mod just ensures that the red circuit is continuous when the ignition is on, it seems that on his vehicle at least, the voltage stays within range.

 

The vehicle specific trick is to find the correct circuit (that is, a circuit that is energized when the ignition is on but off when it is not). Modern cars often have this stuff computer controlled and the correct circuit might be harder to access/locate. On some engine it might be easy to just use the circuit that feeds the coil. But that might be hard to locate on some cars with solid state ignition.

 

So, poster, please give us more detail or suggestions on the best place to tap.

Well said! Exactly what I was thinking

I wonder if some sort of capacitor would do the trick? I guess it depends how long you are cranking the car as well...

Yeah, that is very annoying. Sometimes. like when adding gasoline, I pull up to the pump and want to leave the audio playing (especially while streaming over BT). So I shut-down the engine and leave the key in the Accessory position. But when I restart the engine - the AVIC reboots. A very annoying side-effect of this is that it seems to wipe-out the iPod VR catalog. It has to do a full rebuild afterwards - takes several minutes instead of a few seconds like a reboot from a power-off condition.

 

I expect the poster's mod would be very vehicle specific. I had thought of doing something similar, but I wasn't sure if the power drop causing the reboot was from the Red (switched) or Yellow (constant +12V) feeds. I also wasn't sure it it was just caused by a voltage drop while cranking the starter, or if it was an intentional safety feature to keep the voltage drop from damaging accessories. The Z1x00 manual says the power source required is 10.8 - 15.1V DC, and I wouldn't be supprised if the car's battery dropped lower than 10.8 due to the high amperage draw when the starter cranks.

 

Since the posters mod just ensures that the red circuit is continuous when the ignition is on, it seems that on his vehicle at least, the voltage stays within range.

 

The vehicle specific trick is to find the correct circuit (that is, a circuit that is energized when the ignition is on but off when it is not). Modern cars often have this stuff computer controlled and the correct circuit might be harder to access/locate. On some engine it might be easy to just use the circuit that feeds the coil. But that might be hard to locate on some cars with solid state ignition.

 

So, poster, please give us more detail or suggestions on the best place to tap.

You are right about it being annoying to go from Accessory to Starting the vehicle and the HU rebooting, that is what I was referring to. The mod is not vehcile specific. Every vehicle (except below) has a "True Ignition" circuit in the ignition harness which usually doesn't drop below 9 volts during the start cycle. If it drops to ZERO, keep looking. You should NOT need to do this to the yellow or hot wire for the HU. It should not drop out during start. If it did, all head units would lose thier station presets and clock memory. The whole reason for your radio (heater, A/C, lights, etc) to "drop out", is because it allows the starter to have as much power possible, to start your vehicle.

You may have an issue if your car has a data bus or transponder type key, to start the vehicle. You just have to look else where in the vehicle for true ignition. Here's an example..... A 2011 Volvo SC90 uses a data type key to start the vehicle. There was no true ignition on the harness, most wires were around 3 volts. I found true ignition in the head light harness.

I did this to my 2006 F250 and it works perfectly. You can be watching DVDs, have the navigation or any other function of the HU operating in the accessory position and start your vehicle without waiting on it to reboot and/ or having to click "OK" (again if you already have) on the nav screen, rebuilding your VR catalog, etc.I was annoyed by the "reboot" when I just got the head unit and was learning the features of the HU and was in the middle of something and then wanted to drive it around the block to check out the Nav. blah blah blah

If you would like a good reference for your vehicle, go to www.the12volt.com and look up the alarm info for your vehicle. IGNITION wire is usually the same as True Ignition under thier reference. It is a good handy source and will point you in the right direction.

You may have about $1.00 in parts to do this. Labor depends on your 12 volt ability... it could be free to costing you s shit load of money, because you screwed something up!

You are right about it being annoying to go from Accessory to Starting the vehicle and the HU rebooting, that is what I was referring to. The mod is not vehcile specific. Every vehicle (except below) has a "True Ignition" circuit in the ignition harness which usually doesn't drop below 9 volts during the start cycle. If it drops to ZERO, keep looking. You should NOT need to do this to the yellow or hot wire for the HU. It should not drop out during start. If it did, all head units would lose thier station presets and clock memory. The whole reason for your radio (heater, A/C, lights, etc) to "drop out", is because it allows the starter to have as much power possible, to start your vehicle.

 

You may have an issue if your car has a data bus or transponder type key, to start the vehicle. You just have to look else where in the vehicle for true ignition. Here's an example..... A 2011 Volvo SC90 uses a data type key to start the vehicle. There was no true ignition on the harness, most wires were around 3 volts. I found true ignition in the head light harness.

 

I did this to my 2006 F250 and it works perfectly. You can be watching DVDs, have the navigation or any other function of the HU operating in the accessory position and start your vehicle without waiting on it to reboot and/ or having to click "OK" (again if you already have) on the nav screen, rebuilding your VR catalog, etc.I was annoyed by the "reboot" when I just got the head unit and was learning the features of the HU and was in the middle of something and then wanted to drive it around the block to check out the Nav. blah blah blah

 

If you would like a good reference for your vehicle, go to www.the12volt.com and look up the alarm info for your vehicle. IGNITION wire is usually the same as True Ignition under thier reference. It is a good handy source and will point you in the right direction.

 

You may have about $1.00 in parts to do this. Labor depends on your 12 volt ability... it could be free to costing you s shit load of money, because you screwed something up!

Amarillo6oh,

Thanks for the details and the www.the12volt.com reference source. Unfortunately, the info for my car ('10 Porsche Cayman) is missing. Closest is '04 Boxster, which doesn't even have Alarm/Remote Start info. The most recent with Alarm/Remote info is '99. Porsche has a lot of common systems across all models, but a lot has changed since '99. Also, it ('99) says Ignitiion is Black. Does that sound right? I thought black was more-or-less universally -12v.

One odd thing about modern Porsches, there is no ACC position. ACC is on whenever the key is inserted. There is an ignition and start position. If I can get to the wiring bundle (1st challenge), I'll try testing the black. That is, unless you have any other ideas or suggestions.

One question, is it likely there is a fuse in the fuse-box for the ignition circuit? Maybe DME? That would be the easiest place to tap and undo in case warranty work is needed.

Amarillo6oh,

Thanks for the details and the www.the12volt.com reference source. Unfortunately, the info for my car ('10 Porsche Cayman) is missing. Closest is '04 Boxster, which doesn't even have Alarm/Remote Start info. The most recent with Alarm/Remote info is '99. Porsche has a lot of common systems across all models, but a lot has changed since '99. Also, it ('99) says Ignitiion is Black. Does that sound right? I thought black was more-or-less universally -12v.

 

One odd thing about modern Porsches, there is no ACC position. ACC is on whenever the key is inserted. There is an ignition and start position. If I can get to the wiring bundle (1st challenge), I'll try testing the black. That is, unless you have any other ideas or suggestions.

 

One question, is it likely there is a fuse in the fuse-box for the ignition circuit? Maybe DME? That would be the easiest place to tap and undo in case warranty work is needed.

I have no experience with Porsches. I would guess thatis is a data bus type system. You could just call you local car stereo shop and tell them what you are looking for and they may be able to help you. Good luck.

anyone know about the true ignition 12v on a 2008 Mercedes Benz E350 with SmartKey / Push start system ?

Thank you.

I found it quite annoying that the system would reboot every time I needed to start my truck.

 

All you need to do is add a fused 12 volt wire from your "True Ignition" circuit from you ignition harness WITH a diode, right into the red switched wire on the head unit. Have the band of the diode going towards the head unit - VELLA !!

 

The diode blocks the 12 volts from feeding back into the Ignitoin circuit, when you have your key in the Accessory posistion. You should be able to find them at Radio Shack of maybe a car audio shop will give you one!

 

True Igniton = 12 volts does not drop out during the start cycle.

I'm gunna give this mod a try thanks for posting this thread!

That said, what diode did you use? How many amps does it put through?

I found it quite annoying that the system would reboot every time I needed to start my truck.

 

All you need to do is add a fused 12 volt wire from your "True Ignition" circuit from you ignition harness WITH a diode, right into the red switched wire on the head unit. Have the band of the diode going towards the head unit - VELLA !!

 

The diode blocks the 12 volts from feeding back into the Ignitoin circuit, when you have your key in the Accessory posistion. You should be able to find them at Radio Shack of maybe a car audio shop will give you one!

 

True Igniton = 12 volts does not drop out during the start cycle.

Has this been done? how well does it actually work? I too am annoyed of this rebooting issue, just want to make sure before I try it on my 130bt!

I used a 12v relay from Radio Shack. Must be electronic type, not automotive type. I took 12V (from the yellow wire actually) to the relay (you need to solder or have someone do it for you). The other side of the switch (relay) goes to the red wire. I then took a line from the accessory (was already there to the AVIC) to a 1Amp diode (neg side). On the pos side of the diode I connected a 4700uf capacitor (also from RS)and soldered this to the coil of the relay. The other coil wire went to ground.

There is, in my case, a 3 second delay of the unit shutting down. Restarting does not cause a reboot, and even after turning off the key and opening the door, I'm sometimes shutting the door before the unit shuts down (disconcerting to service men, I have to tell them it's ok). Works for me.

hg

I used a 12v relay from Radio Shack. Must be electronic type, not automotive type. I took 12V (from the yellow wire actually) to the relay (you need to solder or have someone do it for you). The other side of the switch (relay) goes to the red wire. I then took a line from the accessory (was already there to the AVIC) to a 1Amp diode (neg side). On the pos side of the diode I connected a 4700uf capacitor (also from RS)and soldered this to the coil of the relay. The other coil wire went to ground.

 

There is, in my case, a 3 second delay of the unit shutting down. Restarting does not cause a reboot, and even after turning off the key and opening the door, I'm sometimes shutting the door before the unit shuts down (disconcerting to service men, I have to tell them it's ok). Works for me.

hg

Excellent, sounds like just the solution I was looking for. Can you give a detailed parts list (RS part #s would be great!). It sounds like a fairly simple circuit, but a diagram would be great. I'm sure many people here would appreciate it.

I don't know how to add diagrams here, but I'll explain as well as I can.

I used a RS relay - part number 275-0249. I soldered (in the house) 4 connections to it. Across the contacts (the switch) I soldered a wire to each side. I used a RS diode - part number 276-1103 (or you can use an 1104 if you have one on hand as I did), and soldered the + (banded side) to a RS part number 272-1022 capacitor's + side, then soldered this to one side of the coil (it doesn't matter which side either). I also soldered a short piece of wire to the neg side of the diode as well.

Now--- I soldered a piece of wire, about 4" length (you'll figure the length yourself in your setup) to the other side of the coil and ran it along side of the capacitor and hooked the neg of the capacitor to this. I then (actually at the same time) added an additional length of wire to this negative connection. I checked all connections, then wrapped everything in black electrical tape so I had a small black package with 4 (marked) wires coming from it. Be sure to mark which wire is which. Use masking tape or I used the end of a trailer wiring kit which had 4 different colored wires. Write down which is which. Don't rely upon memory.

Now out in the vehicle, using wire crimps, I connected the capacitor negative to a good ground. I cut (broke apart actually) the connection going to the red wire of the AVIC. To the wire COMING FROM THE VEHICLE, I connected the wire going to the diode. To one side of the switch (again, doesn't matter) I hooked the red wire going to the AVIC. The last connection is to any 12V source that's always on. The Yellow wire going into the AVIC can be spliced into. Do NOT separate the connection, just splice into it. Actually, I ran a new heavier fused wire directly from the battery to the yellow line, then tapped into it. This stopped my AVIC from rebooting for no reason.

That's it. Hope it helps. Good luck to you.

hg

Harvey, I am not a complete novice at circuitry, but I'm trying to draw a schematic of this and my head is starting to hurt. It seemed so simple in your inital post, but now I'm confused. Mainly, the relay you used is DPDT, which has 6 contacts (not counting the 2 for the coil). I downloaded the spec sheet for it.

What I came up with relys on two assumptions I'd like you to verify:

1. You only use one side of the DPDT (a DPDT is essentially two SPDTs) - so could I use a SPDT?

2. Assuming you only needed a SPDT, which contact contacts are used? I'm guessing Common (out to the HU RED) and the Normally Open side (coming from the diode/cap).

If you really needed a DPDT, I'm lost. Sorry for the dumb questions, I'm pretty rusty and not exactly solid on the terminology. BTW, I understand what you are doing with the diode/cap and think I understand the polarity issues. Once I've got this 100%, I'll try posting a schematic.

RonS

Sorry. I've been away. I work week-ends.

You are correct. You can use a SPST switch (relay). Even though this relay has a high enough rating, it's also cheap enough to use, and I double contact it. Any idea what I mean? I use both sides of the SP switch. I solder them in paralell (now that can't be spelt right - oh well). I use both of the DP connections. Is this needed? No. Then why? It's just my security/backup in case of a contact malfunction (if the coil fails, it needs replaced). Once the dash is all back together, I don't want to have to return to it unneccessarily. So, ... sorry for confusing you, but you only need the relay to act as a switch (replaces the key).

hg

Well, I collected an assortment of parts I found lying around home and office (not the same part # as you used. Basically 12V SPST digital relay, a cap, and a diode. Started soldering and quiclky realized I wasn't going to make a nice neat bundle out of this. Then, I accidently broke off one of the solder leads on the relay (coil), and gave up.

Then I thought, there must be some off-the-shelf solution - this application isn't that unique!

So I googled "relay delay", and found the PAC TR-7. (through Amazon $19.49 linky) It does many things, and is primarily used as a parking-brake bypass for Alpine NAV units. But is also is a relay with a programmable delay for both ON and OFF (up to 4 min:15sec). The manual makes it look a little daunting to program, but many have said it isn't that complicated Manual. See feature #12. Only 4 wires are needed for this function (ground - black, +12 V - red, ACC - green, 12v out - blue).

Installation of the unit is very similar to your design. So for those who:

• would have to buy the parts anyway (probably $ 12 - 15 @Radio Shack or more if you buy a plastic case).
• don't have the skills or tools to fabricate it.
• want to have more control over the OFF delay

then this is a nice clean solution. I just ordered one for myself. I figure my time is worth a few extra bucks.

Harvey, thanks for leading the way and designing a nice solution to the rebooting issue. You proved it could be done.

Late addition: I discovered that the ACC cut-off (while starting) wasn't my only issue. Seems that the factory radio harness +12V that I am using to power the AVIC also drops voltage or cuts out while cranking the starter. I will need to run a direct +12v circuit from the battery to eliminate this drop. That means I'll have to pull the HU. Project just got to be a big pain-in-the-rump!!! Which means I'll wait until I decide whether to add BU camera & BU wire. I'll just live with reboots till then.

Glad you found a solution. And thanks for finding a $20 relay to do the trick. I had found one, but it was a commercial unit for fire trucks, etc, and it was in the $80 range, so I went to my solution. (...and actually I added a second capacitor to get a 6 sec delay, but that's another story).

Hope it all works out for you. Glad to have (I hope) helped.

hg

I'm gonna try this same thing, but am lost without pictures.

Any help?

I'm gonna try this same thing, but am lost without pictures.

Any help?

First, a disclaimer: I never got this to work on my car. It seems that the voltage drop while cranking is too much to keep the HU from rebooting. I think this may be solvable, but I didn't feel like it was worth the effort. Maybe an oversized battery will help. That will have to wait a while since mine is only 18 months old. Another possibility is that my factory radio's constant +12v wire really isn't constant. To test that, I'd have to remove the HU and run a fuse protected wire directly from the battery. Again, not worth the effort at this time. So, the solution here is somewhat vehicle dependent.

I'm not sure what level of explanation you are looking for. If you have some background in electronics (even introductory); understand what a diode, capacitor, and relay does, then you should be able to draw a diagram with the info here. You need to deal with polarity issues with the diode and cap. You also need an understanding of how the HU is installed (especially the two power feeds). The HU requires constant +12V (yellow wire) and a switched +12v ACC (red wire) which turns ON/OFF the unit with your ignition switch. The problem we want to solve is that most ignition switches drop the ACC +12v momentarily when the key goes from ACC (or ON) to Start. So this causes the HU to reboot. The solution is to not actually feed the ACC wire to the HU, but to run the red wire to a relay - and through the stored energy in the cap, bridge the short voltage drop (over the red HU wire) for a few seconds until the ignition switch returns to the On position. For this to work, however, the constant +12v (yellow wire) needs to maintain at least 10.8v (minimum operating voltage) while the starter is cranking.

Since the original wiring for your installed HU may differ, I'll ignore exactly where the red & yellow wires are connected/fused. Just know that the HU red wire is switched, yellow is constant.

What you want is to cut the red wire and run it through: a diode, then a capacitor (which acts like a storage battery), then one coil terminal of the relay. The other coil terminal goes to ground (-). So now we have a short delay before the relay turns off the "switched" circuit. On the "switched" side of the relay, connect one lead to the other end of the red wire to the HU. The other "switched" terminal needs constant +12V. You can either tap off the yellow wire, or run a fuse protected wire from either your battery or fuse box.

ACC -------(red)-->------/Diode/-->-Cap----->relay(coil)------->ground (good idea to use black wire here).

Battery/fuse +12v constant ------------relay switch----------(red wire)---------> HU

Battery/fuse +12v constant ------------(existing yellow wire)-------------------> HU

Note: Harvey specified a DPDT relay, which is more complicated. In this explanation, I'm using a normally open SPST relay, which only has 4 connection terminals - all of which are used. Two for the coil (trigger) and two for the switched circuit (load).

Now, instead of all that soldering and gathering of parts that Harvey designed, you can just buy the device I mentioned in my previous post (PAC TR-7). It does essentially the same thing and more. Being solid-state, it is programmable with various delays. it would be wired:

Battery/fuse +12v constant--->>>>>---(existing yellow HU wire)-----> HU

blue TR-7 wire -------------->>>>>---(connect to red HU wire)------> HU

ACC ------------------------->>>>>-----green TR-7 wire

(- ground) ------------------<<<<<-----black TR-7 wire

Battery/fuse +12v constant--->>>>>-----red TR-7 wire

A simpler explanation:

--cut existing red wire and splice hot end to TR-7 green

--splice TR-7 blue wire to the red to HU (the other end of cut

--connect a tap off existing yellow wire and splice to TR-7 red

--connect TR-7 black wire to ground

Note: it would be much easier to program the TR-7 before installing it. Programming it will require a 12v source. Read and follow the rather instructions to program the TR-7 and the delay. Manual: see feature #12. If absolutely required, you can probably do this after the install, but it will require removing power from the red TR-7 wire, and grounding the previously unused brown wire . You will need to be able to see the LED on the TR-7.

Hope this helps.

First, a disclaimer: I never got this to work on my car. It seems that the voltage drop while cranking is too much to keep the HU from rebooting. I think this may be solvable, but I didn't feel like it was worth the effort. Maybe an oversized battery will help. That will have to wait a while since mine is only 18 months old. Another possibility is that my factory radio's constant +12v wire really isn't constant. To test that, I'd have to remove the HU and run a fuse protected wire directly from the battery. Again, not worth the effort at this time. So, the solution here is somewhat vehicle dependent. I'm not sure what level of explanation you are looking for. If you have some background in electronics (even introductory); understand what a diode, capacitor, and relay does, then you should be able to draw a diagram with the info here. You need to deal with polarity issues with the diode and cap. You also need an understanding of how the HU is installed (especially the two power feeds). The HU requires constant +12V (yellow wire) and a switched +12v ACC (red wire) which turns ON/OFF the unit with your ignition switch. The problem we want to solve is that most ignition switches drop the ACC +12v momentarily when the key goes from ACC (or ON) to Start. So this causes the HU to reboot. The solution is to not actually feed the ACC wire to the HU, but to run the red wire to a relay - and through the stored energy in the cap, bridge the short voltage drop (over the red HU wire) for a few seconds until the ignition switch returns to the On position. For this to work, however, the constant +12v (yellow wire) needs to maintain at least 10.8v (minimum operating voltage) while the starter is cranking. Since the original wiring for your installed HU may differ, I'll ignore exactly where the red & yellow wires are connected/fused. Just know that the HU red wire is switched, yellow is constant. What you want is to cut the red wire and run it through: a diode, then a capacitor (which acts like a storage battery), then one coil terminal of the relay. The other coil terminal goes to ground (-). So now we have a short delay before the relay turns off the "switched" circuit. On the "switched" side of the relay, connect one lead to the other end of the red wire to the HU. The other "switched" terminal needs constant +12V. You can either tap off the yellow wire, or run a fuse protected wire from either your battery or fuse box. ACC -------(red)-->------/Diode/-->-Cap----->relay(coil)------->ground (good idea to use black wire here). Thanks, that does help alot. What I was more or less confused about was the directionality of the diode and capacitor with respect to +/- sides and the coil side of the relay. "+ (banded side) to a RS part number 272-1022 capacitor's + side" Banded side is the cathode and -. I guess I'm just not reading correctly or it was a typo on his part. The next part I don't understand is the purpose of that "non-bosch" style relay. Is the attached diagram correct? Battery/fuse +12v constant ------------relay switch----------(red wire)---------> HU Battery/fuse +12v constant ------------(existing yellow wire)-------------------> HU Note: Harvey specified a DPDT relay, which is more complicated. In this explanation, I'm using a normally open SPST relay, which only has 4 connection terminals - all of which are used. Two for the coil (trigger) and two for the switched circuit (load). Now, instead of all that soldering and gathering of parts that Harvey designed, you can just buy the device I mentioned in my previous post (PAC TR-7). It does essentially the same thing and more. Being solid-state, it is programmable with various delays. it would be wired: Battery/fuse +12v constant--->>>>>---(existing yellow HU wire)-----> HU blue TR-7 wire -------------->>>>>---(connect to red HU wire)------> HU ACC ------------------------->>>>>-----green TR-7 wire (- ground) ------------------<<<<<-----black TR-7 wire Battery/fuse +12v constant--->>>>>-----red TR-7 wire A simpler explanation: --cut existing red wire and splice hot end to TR-7 green --splice TR-7 blue wire to the red to HU (the other end of cut --connect a tap off existing yellow wire and splice to TR-7 red --connect TR-7 black wire to ground Note: it would be much easier to program the TR-7 before installing it. Programming it will require a 12v source. Read and follow the rather instructions to program the TR-7 and the delay. Manual: see feature #12. If absolutely required, you can probably do this after the install, but it will require removing power from the red TR-7 wire, and grounding the previously unused brown wire . You will need to be able to see the LED on the TR-7. Hope this helps.

Thanks, that does help a lot. What I was more or less confused about was the directionality of the diode and capacitor with respect to +/- sides and the coil side of the relay. "+ (banded side) to a RS part number 272-1022 capacitor's + side" Banded side is the cathode and -. I guess I'm just not reading correctly or it was a typo on his part. <BR>As for the relay, I can just put a jump across both switch terminals, and another across both common terminals? Is the attached diagram correct?

I think your diagram is right. I can't see the marking on the diode, but the banded side should be toward the cap. BTW, I had other parts laying around, and I made up a prototype, which seemed to work when bench testing. I just threw away my diagram on Sunday. I can never remember the diode markings, so I just test with a multimeter to see which way the current flows. Obviously, if it is reversed, the relay wont even energize.

Sounds like you known as much, or more, about this stuff as me. When I broke one of the leads off my relay during the bench test, , I decided against this DIY approach and when I found the TR-7, I decided "why bother".

Good luck.