Reverse wire, parking brake wire, and speed indicator wire

[gvsho]

Hi all. I’ve searched the threads here but can’t seem to find a definitive answer on how to find and tap into the reverse gear (must have), the parking brake, and the speed wires. I’m trying to install a new head unit and backup camera.

Without tearing open the main harness that comes near the radio area the only two places I can see to find the reverse wire is either in the multi connector port in dash by driver left leg OR possibly pulling up the center console and find it as it come up from the transmission. And once I did it I’m unsure of what to do with it next. I’m assuming I just cut the positive wire coming from the transmission and make 2 connections coming from it. One to attach to where it was originally going and another to my reverse gear wire on the head unit. Is that right?

Any help finding it and how to do it would be greatly appreciated. My son and I are planning a cross country drive in a few days and I’d really like to get this working.

Greg

 

[hear]

The parking brake wire is probably just to enable/disable some screen feature. You can *probably * just ground it and have it work fine. Or maybe it needs 12V, so just splice it into the same switched power you used. The point is that you don't NEED to find the parking brake wire (wait....do our TJ's even have a parking brake sensor??).

You definitely aren't going to have a speed wire, but again, that's likely tied to some safety feature related to watch dvd's while you're driving. I'm sure Zorba has an opinion on multi-function stereos as well, lol.

The reverse wire is how your deck knows to flip over to the backup camera screen, so anything that has 12V on it will work if you have the ability to manually switch the screen, otherwise splice into any wire that has 12V on it whenever you're in reverse. The wire off the NSS (which comes across the trans and can probably be spliced into there and Brought into the tub from the trans tunnel hole) is probably where I'd take it from because it requires the least amount of harness surgery to access. YOu'll also need to give power to the camera, which is normally done by tapping into the reverse light wire at the taillight. As far as which wire, the diagrams are in one of the subforms here. Find the one for your year, section 8W.

I will add that if your trip is in a few days, you likely don't NEED a backup camera either. So the stereo & speakers is probably the minimal wiring you need to do.

 

[CharlesHS]

Hi all. I’ve searched the threads here but can’t seem to find a definitive answer on how to find and tap into the reverse gear (must have), the parking brake, and the speed wires. I’m trying to install a new head unit and backup camera.

Without tearing open the main harness that comes near the radio area the only two places I can see to find the reverse wire is either in the multi connector port in dash by driver left leg OR possibly pulling up the center console and find it as it come up from the transmission. And once I did it I’m unsure of what to do with it next. I’m assuming I just cut the positive wire coming from the transmission and make 2 connections coming from it. One to attach to where it was originally going and another to my reverse gear wire on the head unit. Is that right?

Any help finding it and how to do it would be greatly appreciated. My son and I are planning a cross country drive in a few days and I’d really like to get this working.

Greg

Greg,

You have 3 TJs listed in your Profile so I am not sure which FSM to link for you.
In the TJ Resources you can download a PDF for your year TJ.
Look in section 8W for the wiring color and harness connector pin out for the wiring you are looking for.

https://wranglertjforum.com/threads...ice-manuals-fsm-technical-documentation.4618/

 

[gvsho]

Hi…I actually did have 3 TJs but now I’m down to just 2. The one I’m working on is the 2000. I’ll try to find the wiring diagram but the only one I saw was for a 1999. Not sure if they’re the same or not.

Thanks for your post.

 

[TJ Jim]

For the reverse wire I tapped into the rear light backup light. Like you I didn’t want to damage the main wiring harness so my tap is in the light housing side of the plug. The rear lights are easily replaceable if something goes foul

 

[hear]

For the reverse wire I tapped into the rear light backup light. Like you I didn’t want to damage the main wiring harness so my tap is in the light housing side of the plug. The rear lights are easily replaceable if something goes foul

I assume you used that to power the camera, but usually the deck needs a "reverse sense" wire to tell it to flip the screen to the camera output. Did you run that splice back up to the head unit?

 

[TJ Jim]

I’ve got an alpine in my 2015 jk and a Boss in my tj and both use the reverse signal to both power the camera and signal the radio to show the camera view.

 

[hear]

I’ve got an alpine in my 2015 jk and a Boss in my tj and both use the reverse signal to both power the camera and signal the radio to show the camera view.

Right, but we don't have a reverse sense wire in the TJ radio harness, which is why I specifically asked. In my JK I powered the camera off accessory power so I could switch to the camera whenever I wanted. Comes in handy on the trails every now and then.