Hey Guys,

I used to have two problems with my OEM sub on my 2005 F150:

1. Sub crackling during songs and even when unit is off. Kind of like a buzzing and such.

2. Loud thump on startup.

Per Ducati's suggestion I built the 5V reducer with a .1uf cap on one side and three .1uf caps on the other. This got rid of the sub thump.

Then I heard from a guy at CC that a bad ground is usually the problem of sub crackeling. But to test it and see if it's the sub, disconnect the red and whites and see if the sub crackles. I did this and didn't have any crackling for awhile. So I assumed my problem was that I had taped the red and white connectors together (side-by-side) to prevent ratteling and was thus getting interference on the grounds (outside gold parts of the connectors). So before taping them together to prevent ratteling, I went ahead and taped them separately to cover the gold ground area of the RCA connectors.

For a week I've been crackle and thump free. Now I'm getting a crackle from the sub again, however no thump. I'm frustrated as all heck and am about to give up completely on this dumb thing.

Can someone give me a suggestion or help...please.

Thanks again,

Duke

Wow Duke...I wish I could help you! The only suggestion I could offer is to check your "turn on" voltage and see if your regulator is still working.

By the way...is there any way moisture could have got to anything? Someone spill something in the truck?

03Aviator said:

Wow Duke...I wish I could help you! The only suggestion I could offer is to check your "turn on" voltage and see if your regulator is still working.

By the way...is there any way moisture could have got to anything? Someone spill something in the truck?

Nope, no moisture what so ever. Tomorrow after work I'm going to take apart the dash panel again and double check the 5V reducer I built from Ducati's suggestion.

I've had the crackeling problem even before Ducati's suggestion of putting in a 5V reducer to get rid of the sub thump.

It has to be a bad ground at that's the only really good lead I have on this problem.

Where else is this aftermarket harness for the sub grounded besides the RCA plugs?

Could the other RCA plugs on the Z1 side of the harness be causing this interference noise?

Duke

I drew a picture and saved it as jpeg but can't find anywhere to host it. Can someone send me their email address who can post pictures and I'll send them the diagram I drew?

Duke

Found Imageshack. Here is the diagram I drew showing my current wiring.

Duke

wow, I've been doing this for years, and you've throughly confused the s**t out of me :lol: Judging by your wireing schematic you dont have an electrical engineering background? The CC guy told you that it might be a grounding problem, I'm not sure he ment the RCA cables. Somewhere in the loop you have a factory amp. If I were you I would first check all connections on the amp (OEM amp Pwr/Grnd/trn on & sub+/-) If all is secure, I would then investigate how the subwoofer signal is getting to the factory amp. Most Factory amps do not use RCA cables, and perhaps a cheap Line-output converter is the cause of your troubles. Just my two cents, those are the most common problems I run into when dealing with factory amps. Best of luck....

pt4runner said:

wow, I've been doing this for years, and you've throughly confused the s**t out of me :lol: Judging by your wireing schematic you dont have an electrical engineering background? The CC guy told you that it might be a grounding problem, I'm not sure he ment the RCA cables. Somewhere in the loop you have a factory amp. If I were you I would first check all connections on the amp (OEM amp Pwr/Grnd/trn on & sub+/-) If all is secure, I would then investigate how the subwoofer signal is getting to the factory amp. Most Factory amps do not use RCA cables, and perhaps a cheap Line-output converter is the cause of your troubles. Just my two cents, those are the most common problems I run into when dealing with factory amps. Best of luck....

I don't have a electrical engineering background, however, I am a fast learner.

I have no idea where the factory amp is for the OEM sub. It could be built into the hard plastic sub box or behind the seat. Either way I doubt it's something with the amp. I never had this problem when I had the OEM headunit in and it only started when the Z1 was installed. Thus none of the amp and sub connections have been messed with.

What do you mean by "a cheap Line-output converter"?

You're correct in saying I don't have RCAs on the OEM connection. It's a grey plug that the metra harness plugs into. Then the metra harness has two blue and white turn on wires and two RCA connectors which then plug into the Z1 RCA connectors.

Are you saying it could be a bad metra harness?

Could it have anything to do with the fact that my ground wire for the reducer on the turn on wire is grounded to a ground wire that I have all my other ground wires running to? Could this cause interference?

Honestly I wouldn't think so since the turn on wire is supposed to only turn the amp/sub on and off. Then the sound comes through the RCA connections. So do you think the aftermarket "metra" harness that has the RCA plugs on it is bad?

Thanks again for the help!

Duke

F150,
I just installed pretty much the same setup in a 2006 Mustang. My vehicle has an amp for each of the 8" subs in the doors so it was necessary to use both of the "turn-on" leads in the gray Metra harness connector. Although it sounds like your vehicle has only one sub, this may still be your problem. I would connect both those leads together and then connect it to the voltage reg, just to make sure you are turning on that factory amp.

Then, make sure you have insulated the two RCA (one red, one white) from eachother. They should not be allowed to touch their metal pieces together. Then, make sure your grounds are all running to the same place and are on the same gorund circuit as your radio. (in other words: use the ground in the Metra harness for all components. Ford vehicles are notorious for being finnicky when it comes to where the ground goes. (Just ask a Police vehicle converter/installer)!

Oh, and make sure your RCA's are hooked to the "SUB OUT" on the Z1 and not the "FRONT" or otherwise. That could cause too much signal going to the sub which isn't capable of reproducing highs that would go to the fronts, but WOULD cause distortion and popping and fizzing.

Hope this helps.

Upon suggestion that it might be the metra harness I purchased from CC, I went to CC and talked with the store manager who happened to be an older guy who used to run a car stero shop and worked on this stuff forever.

I described my problem and we both went out to the truck (which as usually happens, wouldn't make the noise) and removed the dash panel and looked at the metra harness, Z1 harness and stock harness which are all involved in making the OEM sub and amp work with the Z1.

We believe we identified the problem. It has to be the connection between the stock sub harness and the metra harness for the sub.

The stock OEM sub and amp harness has a plug which has 4 wires going into it. All 4 wires run across the bottom of the plug and I forget the colors of the wires.

The Metra harness has two wires on the top row (not even used on my OEM plug) which run to one of the RCA cables. This makes sense that just in case you have two rear subs, which I only have one. Then the Metra harness has 3 wires on the bottom not four like my OEM plug!

The wire that is on my OEM plug that doesn't have a recieving wire in the Metra plug, is a black wire. So now I need to find out what this black wire does and see if it's the cause of my crackeling which causes the sub to sometimes not work at all, crackel or work fine.

Let me know if you guys know what this wire on the stock plug does.

I'm trying to find Metras 1-800 # too.

Thanks for the help!

Duke

I found this diagram which shows the 4 wires for the 05 F150 audiophile plug. The black wire marked "drain" is the wire that doesn't have anything on the metra harness which connects it.

Does anyone know what the "drain" wire does and what, if anything, it should be connected to?

Duke

I've also seen this wire be labled as the shield wire. So does anyone know what a shield or drain wire is?

Duke

Well I feel like I'm having a conversation with myself.

I called Metra and talked to them about it.

Apparently the black wire from the OEM harness that doesn't connect to anything is the Shield Ground Wire. This wire normally isn't needed but some OEM amps and subs can be "touchy" and need the extra ground.

I will ground that wire later tonight and see if that makes a difference.

Duke

I didn't know for sure on the drain wire so I didn't respond. The shield wire is definitely like another ground, and that is obvious once you start to peel back the tubing most of the wiring harness is in. The shield wires are generally bare and they are run in any high current or noise-sensitive circuits to prevent inducing or receiving "hum" or other electrical interference. It makes sense your drain wire would be an additional ground. Black is generally ground in Fords.

Scooter80 said:

I didn't know for sure on the drain wire so I didn't respond. The shield wire is definitely like another ground, and that is obvious once you start to peel back the tubing most of the wiring harness is in. The shield wires are generally bare and they are run in any high current or noise-sensitive circuits to prevent inducing or receiving "hum" or other electrical interference. It makes sense your drain wire would be an additional ground. Black is generally ground in Fords.

I sure hope we're right. I'm actually going to snap in a wire that will go from that black wire on the OEM sub harness to the ground wire I have running through the HU install harness.

This has been quite the investigation and thanks for helping get in this direction!

Duke

Duke...now I'm confused. I have an Aviator with one sub amp...and it is indeed enclosed in the entire sub unit like yours. Now, and this is totally from memory mind you...my Z1 only has one sub turn on lead. It also has an antenna turn on lead for the antenna amp or power antenna...but I remember only ONE lead for the amp turn on and that is the one you put your 5v regulator into. Now, the Z1 has TWO RCA leads out of it for the sub amp. One is left and one is right. However, since it's a mono signal, you can use just one. Just for grins and giggles, I had a two into one RCA adapter I used. This lead I plugged into the wiring harness adapter. That harness had only ONE lead for the sub amp. I used the factory grounds by connecting them to the appropriate pin in the factory harness through the harness adapter. If I recall, I did ground the sub (it has a separate ground in the factory harness) using the sub ground wire in the harness adapter. I wish I could find the email I sent to Ducatiboy about this. It was specific in detail to exactly what I did. He and I used slightly different methods of hooking up the sub...and both work fine. I hope you get it worked out and you've found your problem!

03Aviator said:

Duke...now I'm confused. I have an Aviator with one sub amp...and it is indeed enclosed in the entire sub unit like yours. Now, and this is totally from memory mind you...my Z1 only has one sub turn on lead. It also has an antenna turn on lead for the antenna amp or power antenna...but I remember only ONE lead for the amp turn on and that is the one you put your 5v regulator into. Now, the Z1 has TWO RCA leads out of it for the sub amp. One is left and one is right. However, since it's a mono signal, you can use just one. Just for grins and giggles, I had a two into one RCA adapter I used. This lead I plugged into the wiring harness adapter. That harness had only ONE lead for the sub amp. I used the factory grounds by connecting them to the appropriate pin in the factory harness through the harness adapter. If I recall, I did ground the sub (it has a separate ground in the factory harness) using the sub ground wire in the harness adapter. I wish I could find the email I sent to Ducatiboy about this. It was specific in detail to exactly what I did. He and I used slightly different methods of hooking up the sub...and both work fine. I hope you get it worked out and you've found your problem!

Yeah, I think you have the wrong idea Aviator. We know the Z1 harness has one lead each for amp and antenna, but the Metra (or other brands like Crutchfield, etc.) harnesses for the F150 and for the Mustang (maybe more as well) have two turn-on leads. I think that is what he meant. I know for sure mine does. I had to use both though because I had two amps (one in each door with the 8" subs).

Ahh...thanks for the clarification. So what you're saying is the adapter harness splits out two leads for amps from the one lead from the Z1?

Precisely. Except that you actually have to connect the two leads as they are separate on the harness. But, yes, once you do that it esentially splits the one to two.

I'll update tonight when I try and ground that wire. I just haven't had time to do it over the weekend.

Duke

Well I grounded the black wire coming from the OEM harness and so far so good (knock on wood). The sub hasn't crackled nor cut out and stoped working. I'm so glad this project is done.

This thread will be a huge help to anyone with a Ford vehicle and OEM sub. This gives the wiring diagram for the sub, the correct way to reduce voltage from the aftermarket headunit to prevent sub thump, and the correct way to make sure the OEM sub doesn't give you performance problems.

Duke

I'm sure glad I grounded that wire when I installed mine. It just made sense to do so. Your problem would have driven me nuts!!

FYI for anyone searching this post. I had a similar problem with my 2004 Ford Explorer, but instead of crackling I had a rhythmic tick coming from the sub (i believe it is called an ignition tick?). I also had a whine that went up in pitch when the engine accelerated. I tried using a ground loop isolator and a noise filter for the power lead but they didn't work. Thanks to this post, I looked at the OEM side of the harness for the black wire and grounded it. The Metra side of the harness did not have a wire corresponding with the black wire on the OEM side (what the F*&# Metra?!!!). Anyway, grounding the wire solved my problem.

Wow, blast from the past.....yeah this was a joyous problem when I first had this. What a major pain in the but and I'm so glad it's over!

what do you mean the OEM harness. There is a floating black wire in the F150's factory installed harness, or do you meant the Metra harness made for our F150.

I cant believe all these people are telling you to check for moisture or bad grounds!!!!!! Its simple, your ford wants to see 5v not 12v.Put a 3k resistor on the remote,or remotes and this will drop it down to the correct voltage.Which means no pop!!!