I'm about to install a brake controller in my truck, and I couldn't find the blue wire (trailer brake control) at the rear of the truck. The truck didn't come with the harness in the glovebox, but It has the blue plug under the dash. I looked for about 10 min. today (it was cold) at the wire loom back there, and couldn't find the blue wire. I was wondering if it terminated earlier in the loom possibly? Anybody know where?

 

According to the information that I can find, a light blue wire should run from the brake controller connecter under the dash to the 7 pin connector at the back bumper. This wire carries the power from the controller to the trailer brakes. I assume that your truck came with a trailer tow package and that you have the correct connector located. It should be located near the left side of the steering column just above the firewall. What color are the four wires at the connector under the dash you have identified in your posting? I just want to confirm you have the right connector.

 

I know it's the right connector because it's the same one that was on the 2002 C&C we have. I didn't install that brake controller because the people who put the flatbed on installed it, but I know it had the pigtail male connector in the glovebox and the salesman showed me where it pluged in. My truck has the same connector, but it didn't come with the pigtail male connector. I didn't see the 7 pin connector today when I looked. Possibly it's under the spare? I don't think the truck came with the towing package, but it does have the connector under the dash.

 

Ok, 7 pin connector not under the spare. Not anywhere near the rear of truck. The wire colors on the female connector are: red, blue, white w/grey stripe, black w/orange stripe. They've got to go somewhere, I just don't know where. Thanks for the help

 

I believe the seven pin connector at the back bumper is part of the trailer tow package. If you don't have the tow package, I am not sure what wiring is or is not there. It could be that all the wires are there except the 7 pin connector. Best bet would be to find a shop manual so you can find the wires that you need. Either way, if the wire is there, it should be light blue according to what they have used over the past few years, including my 97 and now my 03. Sorry I could not be of more help.<br><br>Casey

 

[quote author=erics76 link=board=11;threadid=8773;start=0#84601 date=1040791076]<br>Ok, 7 pin connector not under the spare. Not anywhere near the rear of truck. The wire colors on the female connector are: red, blue, white w/grey stripe, black w/orange stripe. They've got to go somewhere, I just don't know where. Thanks for the help<br>[/quote]<br><br>See if there is a square ten pin connector near center of the back bumper. According to the 03 manual (the only one I have available) that ten pin connector plugs into the back of the 7 pin trailer connector. The only question is if all trucks were made with that connector and it is simply a matter of adding the 7 pin trailer connector. The wiring may not be there at all at the back of the truck if they used a different wiring harness for trucks without the trailer tow package. I believe you can add the trailer wiring to the truck as an add on later. I may be worthwhile finding out what exacly is in the kit. If it is just some minor wiring and relays then the wires should be in the main harness.<br><br>Maybe someone with an 02 wiring diagram can chime in here.<br><br>Good luck. Casey

 

There's nothing back there except wiring for taillights. Tomorrow if I have time, I'm going to chase the infamous blue wire down. I think it's fused, probably in the fuses under the hood. Maybe it terminates there, I'll check tomorrow hopefully. I may look into the kit, but if it comes down to it, i'll run my own blue wire. Thanks for the help

 

I saw a post a while back where someone was trying to figure out what a blue wire coiled up over the left wheel well was for, thinking it was probably trailer brakes. I never heard back on the question of if he had the factory tow package or not.<br>Are you just looking for the termination point of the wiring at the back of the truck? I have a Haynes manual and they have great wiring diagrams but I don't know if that will help, being an aftermarket manual.<br><br>Chris

 

Yes, I'm looking for the termination point of the blue wire that comes out of the connection for the trailer brake controller. The connector has a red wire that's thicker (maybe 12 or 10 ga. ?), a blue wire that's the same thickness, a white with a gray (or brown) stripe that's not as thick, and a black with orange stripe thats the same size as the white one. I'm looking for the blue wire. Thanks for the help.

 

If your truck didn't come with the factory tow package, there is no wiring at the rear of the truck. My 97 didn't come with the factory tow package. I ordered the factory harness for it and it just plugs in. The problem is with the &quot;blue&quot; wire. It terminates in a plug behind the drivers side front tire. You can see it from under the truck. You will see the blue wire coming from the brake controller connector under the dash and it goes into the plug behind the tire. It goes no further though. <br> The factory harness which I purchased from the dealer has the blue wire in it, but you are supposed to run it under the dash to the brake controller. I cheated and installed it in to the back side of the plug behind the front tire. Then I could use the connector under the dash to plug in my brake controller. Never had a problem with the install. The harness was about a $100 canandian if I remember right.<br>Hope it helps.

 

Yep, that's it. Right there behind the driver's front wheel well. I think I'll just tap into it and run my own wire to the back. Thanks for the info.

 

I installed the brake controller today. I cut the blue wire where it goes in the big connector behind the driver's wheel well. Connected my own wire to it (same guage) and ran it to the back. Everything worked fine. Thanks for all the help