2003 Silverado vs. trailer brake light

[masapell]

I checked mine and followed the harness. Though mine did not have the tow package, I believe they still used the same harness and just attached the 7 pin connector end to it. So, with that, the harness does go above the tank and I believe T's into a bigger harness that includes wires from the gas tank, etc. This the appears to go to the fuse center under the hood, where it is fused. If you look at the label on the underside of the cover, you will see abbreviations for trailer (TRL). Check those fuses!!!! Maybe a short on the trailer or something caused one to blow. Again, I don't believe there would be a problem with the wiring, unless it were right there at the hitch. So, the harness should be fine. Let us know what you find.

Sincerely,
Matt

[KaIIen]

Originally Posted by j cAT

I am happy with your pictures. as you can see you have a junction block 4 connectors plug into it . this is bad . replace this and you are good..........

How is the junction bad? The trailer wiring doesn't connect to it, so that can't possible be the problem... Maybe I misunderstand?

[KaIIen]

Originally Posted by masapell

I checked mine and followed the harness. Though mine did not have the tow package, I believe they still used the same harness and just attached the 7 pin connector end to it. So, with that, the harness does go above the tank and I believe T's into a bigger harness that includes wires from the gas tank, etc. This the appears to go to the fuse center under the hood, where it is fused. If you look at the label on the underside of the cover, you will see abbreviations for trailer (TRL). Check those fuses!!!! Maybe a short on the trailer or something caused one to blow. Again, I don't believe there would be a problem with the wiring, unless it were right there at the hitch. So, the harness should be fine. Let us know what you find.

Sincerely,
Matt

The only fuses i found control both turn and break lights. None of the fuses are bad, and the turn signal works. From the fuses to the bulb is the same connection (meaning, there's not a wire for the brake light seperate from the turn signal) the problem must be prior to the fuses. Else-wise, my turn and hazard wouldn't work on that side.

[j cAT]

Originally Posted by KaIIen

How is the junction bad? The trailer wiring doesn't connect to it, so that can't possible be the problem... Maybe I misunderstand?

remove the tape and plastic coverings

[Sonny01]

I had a similar problem and it drove me nuts...it turned out the jack at the back of the truck was bad. Didn't look bad...just was.

[masapell]

Looking more into this and thinking about it KaIIen, I follow what you are saying now. Hope I haven't added too much to the confusion. I looked at the wiring diagrams in my Chilton's manual and here's what I see: The trailer left and right also act as the stop lamps. When the brake pedal is depressed, the input from the brake pedal switch, goes through the turn/hazard switch assembly (these are also run through the flasher to the switch and then to each individual wire or both, depending on turn or hazard) then through the electrical center under the hood, through the fuses, to the hitch. From what I can see on the wiring diagram, the left and right are joined together in the switch, but it is separate from the signal lights on the truck side. Draw your conclusions from that. As for the tail/brake lights on the truck, of course those are all on a separate circuit. So, what do you think? Sorry if this rambles, as I am on my iPhone and am having a tough time seeing my whole post. I don't see any other connections between signal and brake wires in the wiring diagram. Parking lights are on a separate circuit, and those work fine for you.

[j cAT]

Masapell send me your email address. I will give you the details on your park brake question and why this is required this way .