We have a 2001 Suburban (8 liter) towing a trailer. Recently the trailer wiring was repaired, but now when we connect the trailer to the Suburban, the fuse for the trailer park lamps blows consistently and once, the TRUCK'S parking/tail lamp fuse blew instead. There are 12 lamps on that circuit (7 marker/clearance lamps, 1 tag lamp, and 2 dual color/bulb lamps on the fenders). All lamps share a common, strong ground. The thing is, when this SAME trailer is connected to a 2006 Silverado, absolutely no problem whatsoever, even with brakes on to achieve maximum load on the trailer wiring.

Any ideas? As far as I know, the specs for trailer wiring are the same for both vehicles.

FYI, both vehicles have the factory tow package, we are using 7 flat pin connectors with no adaptors.

Thanks in advance!

Also, this is my first post, not sure if this is the right part of the forum for this thread. I don't post in forums often...

 

Greetings Rosariods welcome to the Forum !

There's only one way to check your problem out, and that being
to test each individual circuit out one at a time.

You must verify that the appropriate signal/action, is being sent
to the same Connector Pin on both vehicles.

Then, I would take ALL the lamps out of the housings, and first
verify there there was no short to ground on any of the circuits,
and, that the given circuit was fed through the intended pin
of the Trailer Connector.

Take your time, and keep notes/do a drawing.

Additionally, you may compare the strength/ampacity of the Fuse
which allows the Trailer to be connected and work, with the one
that does not.

Just as a hunch I'll offer...
That I suspect that the Trailer Connector on the Suburban
has been mis-wired, but, I'd still go through each circuit as stated.

 

That pretty much sums it up, I suspect that some wires were crossed or shorted in this repair endeavor...if it was a shop that did the repairs I have them check it out again...

 

Thanks, all.. Regarding the possibility of shorted or crossed wires on the trailer, why then would it cause problems on the suburban and not the silverado?

I should note that when we tested it on the silverado, we only hooked the wiring harness up, we did NOT connect the trailer itself via the towing ball. The suburban was fully hooked up.

The brakes and turn signals work fine when hooked up to either vehicle... I checked the factory harness/plug and it works as it should on both vehicles and the outputs are identical.

We will check the trailer wiring tomorrow, is there anything in particular we should be looking for?

Thanks again!

 

Sorry, I didn't make that clear...

It's the Trailer Connector on the Suburban, not the trailer.

But, given that level of workmanship, I'd still go though the
whole thing as I stated.

 

The 2001 'burb successfully powered this same trailer before the trailer wiring change?

Is the trailer actually connected to the hitch on both the '01 and the '06?