wiring question

[loppydog]

Hi guys I'm new here and have a quick wiring question. I just bought a Avic-z110bt and I am in the process of installing it. My question is regarding the "speed sensor" wire and the "reverse" wire. I know the reverse wire is mostly there for a backup camera, which I do not have. Is there a good reason to connect these wires for other purposes? I know the manual refers to these connections helping with the navigation, is this the true? Maybe someone can help me understand what these wires really do. Any help would be greatly appreciated!

[JasonH]

The speed pluse (vss) will greatly improve navigation accuracy.

[loppydog]

Thanks Jason, do you happen to know the easiest way of finding and splicing into that wire? So as far as the reverse wire, you wouldn't recommend connecting that if there is not a backup camera involved?

 

Also, does the VSS wire have anything to do with the speedometer? the reason I ask is because I have a lift on my pickup which makes my speedo WAY off. I would want the GPS getting incorrect info from my vehicle.

[RonS]

Hi guys I'm new here and have a quick wiring question. I just bought a Avic-z110bt and I am in the process of installing it. My question is regarding the "speed sensor" wire and the "reverse" wire. I know the reverse wire is mostly there for a backup camera, which I do not have. Is there a good reason to connect these wires for other purposes? I know the manual refers to these connections helping with the navigation, is this the true? Maybe someone can help me understand what these wires really do. Any help would be greatly appreciated!

 

The VSS taps into either a pulse wire for your electronic speedo or the ABS controller. All that the Z110 needs is a pulse. It will calibrate over time to figure out how far the car travels with each pulse. So it can dead-recon fairly accurately when the sat signal is lost, or you are in a tunnel or garage, or in a city with lots of sky-scrapers.

 

As you said, not only is the backup sensor for the BU camera trigger, it also tells the Z110 the direction to apply to the VSS pulses. That isn;t so helpful since you typically don't back-up very far.

 

When you start-up your car and start driving, if you didn't hook-up VSS, the Z110 won't know you are moving, so there will be a period of time that it will just show you spining around the same spot (due to the gyro) that it remembered when you last shut-down. I can't tell you how long it will take for the GPS to get a new fix, but it can be 30-45 seconds. It will vary based on lots of things.

 

I didn't hook-up my BU wire, and the only issue I have had is that when I back out of my garage, the satellite fix hasn't occured yet, and the dead reconning logic thinks I'm going forward. Then as I start driving down my street, it looks on the map like I'm driving across my neighbor's lawns. It eventually gets a fix and all is well.

 

It was dumb of me not to run the BU wire since I had to run the ILL wire to my rear parking light anyway. So it would not have been any extra work. Of course both VSS and BU are optional, but they do add value.

 

BTW, the Z110 also has a built-in gyro sensor that can pretty accurately detect your turns, so even in my office parking garage, it still tracks me on the map. Pretty impressive.

[loppydog]

The VSS taps into either a pulse wire for your electronic speedo or the ABS controller. All that the Z110 needs is a pulse. It will calibrate over time to figure out how far the car travels with each pulse. So it can dead-recon fairly accurately when the sat signal is lost, or you are in a tunnel or garage, or in a city with lots of sky-scrapers.

 

As you said, not only is the backup sensor for the BU camera trigger, it also tells the Z110 the direction to apply to the VSS pulses. That isn;t so helpful since you typically don't back-up very far.

 

I didn't hook-up my BU wire, and the only issue I have had is that when I back out of my garage, the satellite fix hasn't occured yet, and the dead reconning logic thinks I'm going forward. Then as I start driving down my street, it looks on the map like I'm driving across my neighbor's lawns. It eventually gets a fix and all is well.

 

It was dumb of me not to run the BU wire since I had to run the ILL wire to my rear parking light anyway. So it would not have been any extra work. Of course both VSS and BU are optional, but they do add value.

 

BTW, the Z110 also has a built-in gyro sensor that can pretty accurately detect your turns, so even in my office parking garage, it still tracks me on the map. Pretty impressive.

 

Thanks Ron!! There is a ton of good info there. From what you have written, It does not sound like an incorrect speedo will affect the GPS at all.

[RonS]

It does not sound like an incorrect speedo will affect the GPS at all.

 

That's correct. You can use the GPS speed to check your speedo - if you can maintain a precise speed over a period of time. I found my speedo is off by about 2 MPH @ around 50MPH. Thank goodness the speedo reading is actually +2, so it gives me a small safety cushion from speeding tickets.

[stoveken]

not optional no excuse not to hook them up. dont know the location/ color i can get it for you jim

[RonS]

not optional no excuse not to hook them up. dont know the location/ color i can get it for you jim

 

I agree that if you paid for an installation, there is no excuse for not hooking up VSS and BU. That is what you paid for. However, the unit does function very well without this, so it is optional in that sense. A DIY'er might decide he doesn't care or didn't want to run the wires. Especially BU, when no camera is installed it adds very little in most situations.