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robertsturf
12-19-2006, 03:10 PM
Ok here goes. I own a 2003 Silverado 2500HD with the towing package. I am having a trailer brake light problem with the right brake light. I have tested at the plug and fuse box and have no power. Other than replacing the harness is there anything else I should check? The fuse box under the hood doesn't list any fuses for the trailer brake lights. The fuse box by the drivers door has the fuses for the trailer brake lights and I have tested for power there. Left brake light on trailer works fine. Thanks for your input.

mojob
12-19-2006, 03:17 PM
Is there a connection at the back of the truck where the trailer plug harness plugs into the truck's harness? I would think think they would tie it in there not up at the fuse panel.

robertsturf
12-19-2006, 03:19 PM
There is a 7 way plug at the rear bumper of the truck and no power at that terminal.

mojob
12-19-2006, 03:32 PM
I'm talking about a connection under the bed that connects the plug to the trucks main harness. I think that's how they hook it up. Follow the wires from the plug toward the front of the truck.

Total.Lawn.Care
12-19-2006, 03:38 PM
Dismount your 7-Way plug and test the bare wires for the power. Sometimes the connections in the plugs either corrode, or become weakened and disconnected and if you test the bare wires and have power, you can just replace the plug by making good connections with new freshly stripped wire and be okay.

Canon Landscaping
12-19-2006, 03:41 PM
there is a fuse under the hood i have an 02 hd and had the same problem there is a fuse inside the cab and under the hood.

robertsturf
12-19-2006, 03:58 PM
I cannot find a marking in the fuse box under the hood for the trailer brake light. The fuse under the dash is good and I am not getting power to that! The 7-way plug in the back would not have power to it if I don't have power at the fuse box. Where would I find the fuse in the box under the hood?? I have looked for the marking several times and no luck.

mojob
12-19-2006, 05:45 PM
If the right brake light worked at one time and now it doesn't and you suspect the fuse under the hood, then just start checking fuses to see if they're blown. If you have 12v on one side of the fuse and zero on the other...bingo. If there's no voltage on either side of the fuse, pull the fuse and look to see if its blown, and if you can't see then check continuity with an ohm meter.

grasswhacker
12-19-2006, 06:43 PM
Dismount your 7-Way plug and test the bare wires for the power. Sometimes the connections in the plugs either corrode, or become weakened and disconnected and if you test the bare wires and have power, you can just replace the plug by making good connections with new freshly stripped wire and be okay.

I had a similar problem and re did the connections at the 7 way plug. Eventually I replaced the lights and the wiring and have not had a problem since. I doubt if it is a fuse, but it is a connection somewhere in the wiring. IMO

hosejockey2002
12-20-2006, 12:26 AM
I had exactly the same problem with my '05 2500HD. The lights on the truck worked fine and no fuses were blown. The dealer replaced the turn signal flasher under warranty. I know that sounds goofy, but it fixed the problem. Is your '03 still under warranty?

Total.Lawn.Care
12-20-2006, 08:26 AM
I had exactly the same problem with my '05 2500HD. The lights on the truck worked fine and no fuses were blown. The dealer replaced the turn signal flasher under warranty. I know that sounds goofy, but it fixed the problem. Is your '03 still under warranty?
Either way, the turn signal flasher is like a $3 part available at any auto parts store. Could be the problem??? Dunno?

robertsturf
12-20-2006, 10:24 AM
I will try the turn signal flasher?? I am willing to try anything at this point. I already have replaced the lights on the trailer. Anything but taking it to the dealer.

grasswhacker
12-20-2006, 10:28 AM
I will try the turn signal flasher?? I am willing to try anything at this point. I already have replaced the lights on the trailer. Anything but taking it to the dealer.

When you unplug from the truck does your right turn signal work?

robertsturf
12-20-2006, 10:56 AM
On the truck or trailer? The turn signal on the truck works fine. It's the brake light on the trailer I am trying to fix. All the lights on the trailer work fine and the back lights are sealed and have been replaced in the last month.

CutNLawns
12-20-2006, 11:30 AM
I just had the exact problem on my truck (03 GMC 2500HD) a week ago. Signals on the truck worked fine. Left turn signal on the trailer worked fine but the right did not. Traced it back to the 7-pin and no power at the plug, no power coming into the plug and the harness goes all the way up to the front of the truck. In the fuse panel inside the cab on the end of the dash there are the fuses (red 10 amp) for the L/H & R/H trailer signals. My R/H was blown. Replaced and things worked fine.

I forget if you said you checked these fuses but if there is no power to that fuse but power to the L/H fuse then it sounds like more of a problem than a flasher to me.

robertsturf
12-20-2006, 12:26 PM
I checked the fuses in the dash panel and replaced just to make sure and they are fine. No power to the right brake light for the trailer. Could it be the Drawtite controller? I have a series 2 controller that was installed when the truck was new in 2003. Does the brake light wiring route through the controller?

grasswhacker
12-20-2006, 01:34 PM
I checked the fuses in the dash panel and replaced just to make sure and they are fine. No power to the right brake light for the trailer. Could it be the Drawtite controller? I have a series 2 controller that was installed when the truck was new in 2003. Does the brake light wiring route through the controller?

Check the wire connections to the plug and to the lights . There should be two one for brake light one for turn signal both for left and right and one for electric brakes. There are little screws in the plug holding the wire in place. Clip off ends just in case it got burnt on the tip, so you get a good connection.
Follow back to the lights to see if possibly one of the wires got hit by a branch or something that disconnected it or cut it.

Total.Lawn.Care
12-20-2006, 01:46 PM
If you cannot get power at the fuse box for the circuit labeled for the right turn sig, then I do not know. Sounds like an issue in the truck someplace. I would go over all of the fuses again just to be sure you have not missed one somewhere. I know that I had an issue once with a short in my trailer wiring and everytime I installed a new fuse, the short would cause it to blow as soon as that turn signal was turned on.


One other thing, i think that in my '01 Chevy, the fuse under the hood is labeled for the turn signals. When I got my '01, the fuse for the trailer running lights was blown, I had blinkers and brake lights, but no running lights. That fuse was under the hood. I can get my book and pin point the fuse locations if you need it. Any help we can give.

robertsturf
12-20-2006, 03:53 PM
Ok so I went to the dealer after trying a bunch of things. (After I had gone to the trailer place that had installed the controller) They found the problem...... Hint it wasn't a fuse bulb or wiring issue. Wasn't the towing package harness either. It was.... a turn signal flasher # 10383321. I had located this earlier but it was very difficult to get to and almost impossible to remove. I wish they would make things easier to work on for guys like us. By the way my extended warranty covered the entire service invoice including the $45.00 diagnosis fee. Thanks again to all who gave their input and opinions!!!

grasswhacker
12-20-2006, 03:56 PM
Ok so I went to the dealer after trying a bunch of things. (After I had gone to the trailer place that had installed the controller) They found the problem...... Hint it wasn't a fuse bulb or wiring issue. Wasn't the towing package harness either. It was.... a turn signal flasher # 10383321. I had located this earlier but it was very difficult to get to and almost impossible to remove. I wish they would make things easier to work on for guys like us. By the way my extended warranty covered the entire service invoice including the $45.00 diagnosis fee. Thanks again to all who gave their input and opinions!!!

:clapping: :clapping: :clapping: :clapping: :clapping: :clapping: :clapping: :clapping: Nice to see problem solved.

Total.Lawn.Care
12-20-2006, 04:51 PM
Glad to see it is fixed. Nice to know that the falsher can cause the whole circuit to loose power. I know that my older Ford had two flashers, but one was for hazzard lights and the other for the blinkers.