Trailer Brakes Problem

[VPayne]

This was also posted on the Accessories Forum.
We hooked up a Prodigy Brake Controller to our truck the other day and went to go pick up our travel trailer from storage so we could use it this long weekend. When we plugged the trailer in to the connecter on the truck, the controller doesn't register that there is a trailer connected. The controller works (has power) just won't recognize a trailer, therefore -- no brakes :-( Well, thinking we had a wiring problem, I went and bought one of those harnesses that has one end to plug in to the truck and the other end to the controller -- no splicing. Still same thing. I even bought another controller to see if this was the problem. Still nothing. We checked everything on the trailer which seems to check out fine. So I called the Tekonsha people and they told me to go get a 12 volt test light and put the clamps on the ground terminal in the 7-pin connecter and test the Brake terminal in the connecter(blue wire) and I should get a code indicating a short on the controller if things are working properly which would then point to the trailer. Well, nothing at all happened. No changed codes which indicates something with the truck. When my husband was initially hooking this up (with the splice method), he accidently had the GM harness plugged in as he was attempting to connect some wires and it 'sparked'. Could this have done something like blown some fuse somewhere that isn't obvious? What else can we check? Maybe factory tow package wiring defect? I called Chevy to see if there was a simple way for them to check whether the was a fault in the truck end of things, so we would know whether to focus on trailer or not, but they said that "it could turn into a long troubleshooting thing" and that they didn't have time to do it today. Please, any ideas!! We really wanted to go on vacation tomorrow.
P.S. Turn signals, stop lights etc work on trailer. :(

[odoh]

I've not hooked my prodigy up yet ~ so I'm not a real authority on it at the moment. But there are some simple things that can be done until someone w/more knowlege chks in. First, perhaps the 40A (?) fuse has blown? Or perhaps not installed? They've discussed that fuse on another thread ~ you can do a search and check it out ~ but if I recall right the consensus was contrary to the GM factory instructions the fuse shud be in the circuit. Another thing would be to verify the controller harness wiring. While hubby is busy chkg that out, perhaps a post on one of the RV forums could be fruitful. Hope something works in time for your vacation. ~ odoh

[Maverick]

Does the prodigy say ".C." If it does the the connection is good. If not then check the ground wire to the controller. Is it hooked up correct? Is the 40 amp fuse under the hood installed? Goes in the top left slot.

This is how you wire the controller if you have't done it already.

Your brake controller should have 4 wires coming from it. The GM pig tail has 5 wires. Connect the wires from the controller to the pig tail as follows:
Controller - Pig Tail

Black to Red
Red to Lite Blue
White to Black
Dark Blue to Dark Blue

Brown wire not used on GM pigtail.

Under the dash, left of the brake pedal is a junction box. Harness plugs into the 2nd from left at the top.

What does your trailer plug look like? Is it a 7 pin RV or are you using a 6 pin to 7 pin adapter? If you are using an adapter you need the one that does NOT have the brake pin in the middle. If the brake pin is in the middle on the adapter it is the wrong one. There is only one other avaliable.

Sounds like a ground to the controller problem though. What kind of connectors did you use? The blue scotch lock type? Junk. Put a butt connector in instead. Can't think of anything else. I'll watch this thread tonight.

:D

[ 05-23-2002: Message edited by: Maverick ]</p>

[VPayne]

We originally installed the trailering harness provided by GM into the slot under the dash and spliced it with the Tekonsha wires and the other end of that plugged into Prodigy. Now we have the trailering harness that has connectors on both ends, so there really is nowhere to err. Just plug in underdash, plug other end into Controller, install fuse. Voila! Finished! We have a 7-pin connector, factory tow package. Is there some fuse somewhere that controls the trailer brakes, like there is a fuse for the trailer Left Turn signal, trailer right turn signal, trailer backup lights etc., but none for actual brakes? Or is that the 40AMP fuse that we installed? I probably just answered my own question.

[IndigoDually]

If the two red dots on the bottom of the display are lit after you hit the brake pedal then the controller has power. It sounds like the truck and trailer configuration don't match. I run all 6 way round connectors and sometimes the pin for the brakes and the pin for the 12v+ charging circuit or accessory lighting are interchanged.

I would first try to switch them on the trailer end first and see if that works. I own 3 trailers from the same manufacturer and the one that I bought used had this done. The truck that I brought home the trailer with had the extra pin wired as the back-up lights. When I tried to back the trailer in the driveway the reverse lights applied 12v to the brakes and locked the wheels on me. Took a little time to figure that one out.

Good luck,

John

[trailguide2u]

As far as the 40amp fuse goes, you don't need it. Unless your charging the batteries on the trailer your pulling. I have not put in the fuse and have had no problems. I posted this question about 4 weeks ago.

[Viking]

The possible clue in this picture is the description "it sparked". It would appear that 12volts was accidently fed to ground, through the controller.

[VPayne]

Viking, my husband says controller was not plugged in when he got the spark.. Connector was loose on that end, only end that was plugged in was on the truck side... But just in case, I already tested out a NEW Prodigy Controller to make sure controller wasn't fried.

[ 05-24-2002: Message edited by: VPayne ]</p>

[VPayne]

Does anyone know what type of place would be able to take the whole setup (truck and trailer) and diagnose problem? An RV Dealer? Obviously not the truck dealer..

[Ironhead]

Hi Vickie, Sorry about your problem right when you want to leave. Yes the RV dealer would be the place to try now. I would think they hook up peoples vehicles all the time when they purchase a trailer. Good luck
something to check, Is the trailer wiring making a good ground connection to the truck? Take the test light and put on the pin for the brakes and ground the other end. have someone step on the brakes to see if test light comes on. If it comes on the problem would be in your trailer.

[ 05-24-2002: Message edited by: Ironhead ]</p>

[JEBar]

Indigodully exactly discribed the problem we had when we hooked up the wiring for our tralier... our problem was the +12 was hooked to the hot line for the trailer brakes, thusly breakes locked all the time..took both truck and trailer plugs apart and found problem, has worked fine every since :confused:

[battmain]

The trailer circuit uses separate fuses. Before you spend too much money for someone to tell you that a fuse is blown, might want to dig up the owners manual and check every fuse that the manual lists as 'trailer.' There is a section that indexes all the fuses by name.

[MNMAX]

Hi, Check to see that the fuse is installed and is good in the under hood fuse center in position STUD 2 * this supply's the braking power ( main power feed )to the controller. STUD 1 * is the one that supply's the power to the trailer charging line. Your controller may show some lights or other signs of power when you apply the brakes due to the stoplight line sending its signal to the controller but this does not mean that the controller has it's supply power. Hope this helps.

[ 05-28-2002: Message edited by: MN MAX ]</p>

[VPayne]

We were able to take our mini-vacation after all! Turned out there was a problem between the end of the blue wire and the associated terminal on the 7-pin connector (bad contact or something). Anyway all is good after all of that TROUBLE! Thanks to all who responded.
By the way, this was our first time towing with this truck and my husband says it is like nothing is even back there and the truck just wants to go FASTER! He had to keep slowing down! It was great. I felt so comfortable, unlike the feeling when we were using our Tahoe to tow our travel trailer. Awesome! And hardly noticed any more fuel consumption than usual, although we were mostly on flat ground. We'll see what happens when we tow in the mountains.