Trailer light wiring harness

[SSalzer]

This doesn't have to do with a CTD but, here goes anyway. Maybe someone can help me out. My brother has an 08 Jeep Commander. I got him one of those "plug and play" wiring harnesses for the trailer lights. I have the correct signals going into the "box" (the box is a sealed plastic junction box)that makes all of the connections. i. e. turn signals, running lights, brake, etc. However, the signals coming out going to the trailer (4 wire) are not right. No right turn signal or brake lights.

I cut the box out and tried to splice the wires together to make it work. Here's my problem. I got the turn signals (green & yellow), running (brown) and ground working properly. There is a red wire coming off of the plug and play kit that runs the brake lights. I can't figure out where to splice this in to? I tried piggy backing it into the brown running light wire, but that obviously didn't work. Can anyone help? Thanks.

 

[Hoefler]

My guess would be that the red wire is for 12 volts to the battery.

 

[SSalzer]

Red is for the brake lights. I just can't figure which one to piggy back it to

 

[steved]

The box took the separate amber turn signals and made them part of the brake light circuit (or vice-versa)... if the green/yellow have "brake" signal when the pedal is depressed, you shouldn't need the red one? If not, then you either got to do some fancy wiring or buy another box.

 

[d6c]

Modern vehicles with amber turn signals on the rear are a separate circuit. Brake lights will be red on a dedicated circuit. Sounds like your "wiring harness" has a trailer converter to output old-style combined turn/brake lights. Most converters go that way, some go opposite, for instance a combined tow vehicle wants to tow a tow-behind amber turn signalled vehicle.

 

[SSalzer]

Green/Yellow do not receive a brake signal. The only wire that does is the red one I mentioned. I can't buy just the box, I need to get a whole new wiring kit. I was trying to save my brother $75 for a new one. I think that's my only choice right now.

 

[d6c]

Assuming that the plug and play kit was vehicle correct if there is four outputs for your trailer plug they should be left turn, right turn, taillight, and ground. Re-read your original post. . this kit did T into the vehicles wiring harness at a weatherproof connector didn't it? If everything was vehicle specific it could be T connector to converter box to 4 flat connector. No splices... No problem. Oh and if you cut the box out and have been combining wires you better make sure everything is working OK on the vehicle. Fuses and TIPM come to mind... isolated system should never be combined.

 

[B.G. Smith]

The converters sold for that purpose have diodes in them to keep the brake lights seperate when using as turn signal or brake lights and to keep the voltage from feeding back into the vehicle wiring. I have a couple of the converters here, if you can't find something better let me know nd I will mail one to you, no charge. These are not plug and play but will require you to tie the wires into tow vehicle wiring. bg

 

[SSalzer]

I went to my local trailer dealership to talk to the guys there. It turns out that a trailer that was pulled with the vehicle had bad wiring and burned out the converter box in the wiring harness. The guy told me that they are designed to burn out instead of damaging the vehicle's computer. I bought a whole new wiring kit and will install it today. Hopefully that will correct the problem. Thanks guys for all of your help.

 

[bighammer]

Sounds like you have it figured out, but since there is no 3rd gen Cummins involved, I moved this to Towing, Hauling, and RV Forum.

 

[SSalzer]

Replaced entire wiring harness on tow vehicle. Problem corrected. Trailer must have shorted and fried the old converter on the harness.

 

[d6c]

First off, glad the problem is resolved. I, for one, am confused as to the order of things that happened. If i have any grasp on the info. it is like the tow rig didn't have a trailer plug at all and you added on and got fouled up doing it . Then a trailer shorted out the converter box? When did that happen? Entire wiring harness on tow vehicle is a huge and very expensive job in itself. If that actually happened my guess would be combining wires really fried everything. Don't get me wrong, I am glad it's fixed.