Chev Silverado / Trailblazer light harness issue

[BoxMN]

So we hooked up the boat tonight to a 05 Trailblazer, and for a few seconds, the side markers worked. Then we only had the blinkers, brake lights that work. The running lights and side markers don't.

So we figure it is ground issue. We try to isolate it a bit, but all seems okay with volt meter, etc.

So we try different 7 pin connecters, and extensions, then try it on my brothers 07 Silverado. Always the brake lights work and the flashers work, but no running lights or side markers.

So we figure we have bad connections in the 4 flat trailer conector. I wanted to try my 98 chev k1500, just to be sure. And what do you know, the trailer works great, all lights, no shorts or any problems at all. The trailer is fine.

So we hook it back up to other trucks and same thing, NO running lights or side markers.

We put the volt meter to my brothers 7 pin and we get no volts for the running lights showing up.

So, my question is, is there a fuse for just running lights to that plug? What the heck would cause that, and why on both trucks? My brother noticed it acting up last time he had the boat out, but wasn't using it at night, so didn't really think anything of it, since the lights were off.

Is there something goofy with the auto lights on the newer chevs?

At least I will be using my 98 this weekend, so I am good, but this has us totally confused. Thanks for any ideas.

[Jeremy airjer W]

You'll find the park light fuse for the trailer in the rear fuse box under the rear seat. It will be marked tr park. Check that first. It is possible that the trailer wiring for that circuit is shorting/drawing to many amps. Checking the fuse is a good start and if it blows again than a good check over of the trailer wiring may be in order.

[BoxMN]

Thanks airjer!

[BoxMN]

Thanks airjer, the fuse on Trailblazer was blown. We will check over the wiring on trailer again. Maybe a worn spot on the brown wire somewhere?.. What else could cause it to blow a 10 amp fuse?...

Thanks!

[Scott K]

An 11 amp draw

[BoxMN]

Always a wise guy in every group haha!

[Jeremy airjer W]