Our new 2003 Sierra has the towing package with 7pin connector. I added
brake control via plug in harness with no problem. The charging (or aux hot)
lead to trailer is not hot at rear plug. Do I need to run the lead or is it
there waiting for a fuse? Any help would be appreciated or I'll have to have
dealer look at it.
Just one question:
Are you checking at the plug itself or at the end of the harness that plugs
into the plug? If you are checking at the end of a harness you probably
have the wrong harness. The 03 harness is unique from the 99-02 harnesses.
They all look alike but the wiring is different. That is the reason for my
question. If you are checking at the plug itself, I don't have the answer
I am checking at the plug at rear bumper. Harness supplied with brake
control was correct 2003 harness and brakes work fine. Instructions with
brake control (none came with harness) do not address the hot lead. I am not
hot on the aux lead at bumper. I would not be surprised to learn that I need
to add a fuse but don't know where in under hood box it would go.
I have a 2003 Silverado Z71 I had the same problem. You need to put
a fuse under the hood in the fuse box. Mine was the top left fuse.
The factory put a fake red solid dummy fuse in it and after I replaced
it it I had power at the rear plug.
Hope this helps.
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