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Backup Signal under Dash

7K views 23 replies 9 participants last post by  AstroWill 
#1 ·
Can anybody help me locate a reverse signal under the dash? It seems stupid to have to run a wire from the tail lights up to the the dash when there is already a wire carrying that signal going the opposite direction.

Am I right to assume the wire is light green (the color of the reverse signal in the tow harness)?

There are 3-4 light green wires coming from the steering column. Would one of those be it?
 
#3 ·
Thanks to those who replied. Several others had posted the same question on this forum looking for a somewhere they could tap into to install a backup camera. There did not seem to be an answer other than "Just wire it back to the brake light/tow package."

Yesterday I poked around and found what I was looking for.

Here is a picture of the backup signal wire.
It is right where Leeann's diagram shows it should be. The wire is light green. It is in a giant bundle of wires leaving the fuse box in the drivers foot well. I think it is the only light green wire in this cluster. In this photo I have already cut the wire and crimped on spade connectors (pink). Hope this is helpful.
 
#4 ·
Thanks for figuring this out! This should be helpful for wireless cameras.

However if you buy a regular reverse camera most have the cable for the reverse signal with the camera cable which you have to run anyways. It was quite easy to fish the cable under the headliner in my case.
 
#5 ·
chr_sei said:
Thanks for figuring this out! This should be helpful for wireless cameras.

However if you buy a regular reverse camera most have the cable for the reverse signal with the camera cable which you have to run anyways. It was quite easy to fish the cable under the headliner in my case.
I am not sure that is how backup cameras are supposed to be set up. At least it wasn't for my head unit/camera.

My head unit, a Sony xav-ax100, connects to the camera by the composite video connection. The head unit has a separate wire, labelled "reverse", which tells the head unit to switch video inputs when the car is in reverse. The video input will switch back when the car is out of reverse. I can also go through the settings and manually change the video input to the back up camera when the car is not in reverse.

Wiring for the camera include 1) a positive lead, 2) a negative lead, and 3) a composite video connection. The positive goes to an accessory power cable (something that turns on when the car is on and off when the car is off) so that the camera is still on if I want to manually change the video input.
 
#7 ·
jimi_lee said:
Thanks to those who replied. Several others had posted the same question on this forum looking for a somewhere they could tap into to install a backup camera. There did not seem to be an answer other than "Just wire it back to the brake light/tow package."

Yesterday I poked around and found what I was looking for.

Here is a picture of the backup signal wire.
It is right where Leeann's diagram shows it should be. The wire is light green. It is in a giant bundle of wires leaving the fuse box in the drivers foot well. I think it is the only light green wire in this cluster. In this photo I have already cut the wire and crimped on spade connectors (pink). Hope this is helpful.
Just stopping by to thank you for your 2018 post and photo. It helped me greatly.
 
#10 ·
Theslaking said:
Jimi lee do you still have a picture of the reverse wire location?
jimi_lee said:
Here is a picture of the backup signal wire.
It is right where Leeann's diagram shows it should be. The wire is light green. It is in a giant bundle of wires leaving the fuse box in the drivers foot well. I think it is the only light green wire in this cluster. In this photo I have already cut the wire and crimped on spade connectors (pink). Hope this is helpful.
03_reverse_lights_firewall_passthrough_400.gif


I will just throw these in here as well.
 
#11 ·
Hey so I'm installing a double din stereo with a reverse camera, and I'm looking for this wire. I have a 99 Astro AWD. I located the light green wire, jammed my meter through the insulation, and grounded out the meter on the chassis, then had my girlfriend shift back and forth. No change in signal to this wire.

Any other ideas? Not sure what I'm doing wrong.
 
#12 ·
Hey so I'm installing a double din stereo with a reverse camera, and I'm looking for this wire. I have a 99 Astro AWD. I located the light green wire, jammed my meter through the insulation, and grounded out the meter on the chassis, then had my girlfriend shift back and forth. No change in signal to this wire.

Any other ideas? Not sure what I'm doing wrong.
FWIW, I connected my backup camera to the switched power line to the radio. Radio on, backup camera works. Park, drive, neutral, reverse. My backup camera is part of my after market, but I would think you could do the same with any camera. Maybe there is some legal/law issue with camera only working in reverse? I don't care, I'm a rebel.:cool:.I actually like having the camera be available all the time. If I've got my curtains closed, I can still have a full view looking out the back.
 
#13 ·
I just tried it hooked up the red wire as you suggested but I'm unable to use my stereo with it hooked up like that. Really need to find teh reverse wire but it's honestly a giant PITA to have someone shifting it with their foot on the brake while I'm crammed in the foot well.
 
#16 ·
Was not aware the wiring changed from year to year, as the year is not stated in this thread and there seem to be diagrams posted here, I was assuming this was fairly universal.

I did take another look and I see two light green wires in that main bundle.... maybe it's the other one?

If I jam my meter into it, and the other probe to ground, and someone shifts to reverse, should it see a constant 12v? Or just a blip of 12v?
 
#17 ·
ADDvanced - maybe this helps? I used this thread to ID the wire for myself - LeSafari - 1997 AWD Build
Thanks, yeah my install will be similar, I just can't find a green wire that does anything. I'm hesitant to cut it and splice into it, but you just used a tap eh? Maybe that's fine for something like this.... I'll try it and see if it works.
 
#19 ·
So I noticed two light green wires in my harness in the footwell. I tapped into one, and it's 12v whenever the van is running so my stereo is stuck in camera mode. I pulled that off, and tried the other green wire, and nothing. I have a 99. Baffling to me this isn't easier to find. This is basically the top result in all of google...
 
#22 ·
Yes, that is why you have to use the wiring diagrams from YOUR year. I looked at the 3rd party wiring diagrams quickly and it looks like your best best is either directly from the park/neutral switch or from the trailer wiring harness bundle by the jack. The lt. green from the park/neutral switch doesn't go anywhere near the drivers footwell for your year.
As always, wiring diagrams are available(see links in sig) if you want to check them out yourself.
 
#20 · (Edited)
As I said, I wired my stereo and camera differently and without seeing the wring for the stereo and the camera, I'd be at a loss to solve this puzzle, At this point, you need a win. I'd suggest is running a temporary jumper back to the taillight power and verify that everything works as it's suppose to. At least you'll know everything else is wired correctly. After that you can resume your mission for the elusive power wire or bite the bullet and run a permanent wire to the rear.

All kidding aside, I added some extensive wiring when I did my conversion. When I added a circuit for whatever device/power I'd do a temporary install to make sure all the components worked as they should before integrating them into the rest of the "system"
 
#21 ·
Yeah the issue is my van is a fully finished conversion van so running wiring would be pretty obnoxious. Really driving me crazy I cannot locate a reverse signal under the dash.
 
#23 ·
Rectangle Slope Font Parallel Pattern

Thanks Will! Didn't know you had all that info! So this is the wiring I found related to shifting.... maybe I'll see if any green wires have a white stripe on them.
 
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