Only ONE trailer brake light. Help!


KaIIen
05-07-2011, 11:49 AM
Hey all. I posted about this last year to no resolve, and now it's time to get out the camper/boat so here I am again....Have an odd issue hopefully someone will have some insight on...

I have a 2003 1500 Z-71. I discovered that I have no right side trailer brake light. I have 2 trailers (RV & boat) and both have this issue. Turn and hazard work, and both filaments in the bulb are fine...since there is only the two wires for the brake/turn/hazard, it is definitely in my truck. I also tested with another Silverado and brake lights work fine.

Sooo, I checked all fuses that I could find related to the trailer harness and all are fine. I called my dealer and explained issue, and the mechanic (yes, actual mechanic) told me that the wiring to the harness runs directly from the truck's (http://www.automotiveforums.com/vbulletin/../#)tail/brake lights. I crawled under there, and no they don't...I was able to trace the bundle from the harness and it goes directly up front. To where, I am not certain as it's path goes above gas tank...

I really don't wanna have it serviced, but so far I am at a loss as to what to look at next. Any ideas? Thanks!

mcmalloy
05-07-2011, 02:58 PM
sounds like your truck came with a factory trailer package, it should plug in at the back of the truck ,the main harness runs from the front , witch plugs into the tail light harness, the trailer harness is plugged in between the two harness's, might have to pull the tail light out to find it,the trailer harness witch they put in is probably faulty , just pick up another trailer harness that plugs in , or you can find where the connection is bad and spice in a new wire for that brake light

KaIIen
05-07-2011, 11:44 PM
sounds like your truck came with a factory trailer package, it should plug in at the back of the truck ,the main harness runs from the front , witch plugs into the tail light harness, the trailer harness is plugged in between the two harness's, might have to pull the tail light out to find it,the trailer harness witch they put in is probably faulty , just pick up another trailer harness that plugs in , or you can find where the connection is bad and spice in a new wire for that brake light

Ok, if I am understanding you, it sounds similar to what the dealer mechanic told me, that the wiring to the trailer plug is connected to the tail lights, and that I should check that connection. Yes, this is a factory package. However, the trailer harness runs directly to the front somewhere. So I have the trailer plug, and all the wiring is inside corragated tubing, and it runs up over the gas tank to the front. I haven't been able to trace it further because on the front side of the gas tank there are 3 or 4 such wiring bundles (the carragated tubing running to various points in the front. There are no wires coming out of that bundle to the trucks tail lights or to the junction connector above the spare.

MT-2500
05-08-2011, 06:39 AM
Hey all. I posted about this last year to no resolve, and now it's time to get out the camper/boat so here I am again....Have an odd issue hopefully someone will have some insight on...

I have a 2003 1500 Z-71. I discovered that I have no right side trailer brake light. I have 2 trailers (RV & boat) and both have this issue. Turn and hazard work, and both filaments in the bulb are fine...since there is only the two wires for the brake/turn/hazard, it is definitely in my truck. I also tested with another Silverado and brake lights work fine.

Sooo, I checked all fuses that I could find related to the trailer harness and all are fine. I called my dealer and explained issue, and the mechanic (yes, actual mechanic) told me that the wiring to the harness runs directly from the truck's (http://www.automotiveforums.com/vbulletin/../#)tail/brake lights. I crawled under there, and no they don't...I was able to trace the bundle from the harness and it goes directly up front. To where, I am not certain as it's path goes above gas tank...

I really don't wanna have it serviced, but so far I am at a loss as to what to look at next. Any ideas? Thanks!

The trailer lights /trailer light plug-in wiring does not connmect to rear truck lights.
They go from trailer plug to the under hood fuse box.
Where there is seperate fuse for each wire.
With turn signals on flashing.
Check both sides of the fuse for that trailer turn signal/brake light that is out.

If no 12 volt power there when stun signal/brake light is on.
The next step is to go to turn signal flasher module.

Ckeck there for trailer turn signal/brake power out of it.
If truck turn signal working and no trailer turn signal out of module then the module is bad.

Best I could figure from wiring diagram on the module there is a seperate power feed out of flasher module for truck and for trailer wiring.

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