Trailer Wire Harness Trouble

[monker]

Hi all. I couldn't find much info on this in the search, so here is goes....

 

I have a 04 silverado that I am towing an enclosed trailer with. All the trailer lights work when verified with a 12v source. When connected to the truck, I do not have a right break light on the trailer. Measuring with a meter at the 7 pin harness on the truck, there is no voltage when the breaks are applied for the right trailer break light. Fuses seem ok, but I did not find one labeled specifically for the trailer brake lights.

 

Any sugestions?

 

Thanks.

[carneyman]

Interesting, I have almost the same problem, only the right brake light and blinker don't work on the trailer. The lights work fine. Oh, and mine is the 4 pin.

[monker]

Hi all. I couldn't find much info on this in the search, so here is goes....

 

I have a 04 silverado that I am towing an enclosed trailer with. All the trailer lights work when verified with a 12v source. When connected to the truck, I do not have a right break light on the trailer. Measuring with a meter at the 7 pin harness on the truck, there is no voltage when the breaks are applied for the right trailer break light. Fuses seem ok, but I did not find one labeled specifically for the trailer brake lights.

 

Any sugestions?

 

Thanks.

 

It is quite odd. The signal even works ok on the same light.

[Taaaaaaahoe?]

Check fuses under hood too!!! Trailer fuses under there. Sure youhave a good ground on your meeter? Try a tail light tester too..

 

99.99 % of time its the trailer grounds, not the truck,,, but forsure check that fuse under hood.

[monker]

Check fuses under hood too!!! Trailer fuses under there. Sure youhave a good ground on your meeter? Try a tail light tester too..

 

99.99 % of time its the trailer grounds, not the truck,,, but forsure check that fuse under hood.

 

 

The trailer is fine (100% sure). ALL fuses in the truck are good too. I checked each one under the hood and in the cab with a meter.

 

Grrrrr.

[blankey]

My 2004 did the same thing when I first hooked up the trailer. The passenger side brake/turn signal light didn't work. When I checked for the power at the plug on the truck there wasn't any. I found the fuse in the driver's side of the dash to be blown, I think it was a 15 amp fuse. I replaced it and have had no trouble since.

[anonemouse]

Had the same problem on my '02 Sierra. Turned out to be a fuse under the hood. GM breaks-out the trailer wiring from the main system and therefore has separate fuses for the trailer lights. It helps protect the main electrical system from over-zealous boat launchers.

[minibike132]

According to the schematic there is a fuse in the i/p fuse block RT TRLR ST/TURN Fuse 10amp. Then the only connection between the fuse and the rear of the vehicle is c102 terminal A Dark green wire. This is a pain to get at if you need to. You need to remove the under hood fuse box and there are a few connectors under there. C102 is a 10 pin connector that contains these colors in this order-Dark Green, Light Green, Light Blu, Brown, empty,Tan/White, Red, Yellow, Light Blue and pink. I hope this helps you.

[monker]

According to the schematic there is a fuse in the i/p fuse block RT TRLR ST/TURN Fuse 10amp. Then the only connection between the fuse and the rear of the vehicle is c102 terminal A Dark green wire. This is a pain to get at if you need to. You need to remove the under hood fuse box and there are a few connectors under there. C102 is a 10 pin connector that contains these colors in this order-Dark Green, Light Green, Light Blu, Brown, empty,Tan/White, Red, Yellow, Light Blue and pink. I hope this helps you.

 

 

Thanks. I'll have to dig a little deeper. It's just really odd that the turn signal works but not the brake light. It would have to be something 'up stream' of the fuse. Having the turn signal working means the fuse and wire/connections are still good.