Ist the TV or the AS?

[Claudiaj]

The "Check Trailer Wiring" light and dinging started about 300 miles into my 1000 mile trip from Reno to Chama, NM. I have checked all the connections, and cleaned the plug and applied electrical grease stuff but the light and dinging continue. Everything works..lights, brakes, turn signals etc.

I did have a low tire and when checked discovered there was a nail casing a slow leak. That was repaired but the light and dinging continue. The only time it stopped was when it rained or when I first start out in the morning. Any thoughts or suggestions?

I called AS in Albuquerque but they can't see me for a month. I will be on my way north to the Oregon Coast at the end of the month. The Chevy repair states it has to be the trailer and not the TV.

[vintagemotor]

You need to have the brakes checked out on the AS. Assuming you have not added anything to the system, this warning indicates that the resistance self test that the Chevy controller performs has failed. Check the wiring to the backing plate on each wheel, if a wire is broken fix it and recheck. If you do not see any broken wires, there could be an issue inside the brake coil winding.
Do not ignore this as you do not have ANY brakes when this message is illuminated.
You can call Dexter axle customer support and they can direct you to many other repair facilities in addition to AS dealers, who may be able to see you sooner.
Dexter axle/brake warranty is 2 years.
Good luck!

[Wingeezer]

I had a ton of trouble with the trailer wiring on my Sierra. But I would get a message slightly different - check "trailer brake system" - I think that indicates a problem on the truck not the trailer itself.

After multiple visits to the GMC dealer - they changed first a trailer brake relay, and then a trailer brake computer module on the truck and EVENTUALLY stopped these error messages and chimes.

Both of those components are located on the truck frame near the rear wheel, drivers side - at least on my 2008 2500HD that is where they are.

Cost me about $400 to resolve !! (just outside warrantee)


It was very frustrating - I never knew if I had trailer brakes or not for a long while! I was getting so p*ssed off with it after so many futile trips to teh dealer that I about ready to see if I could dump the whole GM system and install an aftermarket brake controller!

I have now set myself up now with a DC clamp-on ammeter and a 7 pin trailer extension cord that allows me to easily monitor current flow to the trailer brakes if ever I suspect a brake problem with the trailer - should be around 12 amps under full braking.

I also made a dummy load out of four used brake magnets wired in parallel that I can plug into the truck connector with my ammeter to check the truck itself with my ammeter and so help decide if a problem is truck or trailer related.

These are intended to assist me in future trouble-shooting, but naturally havig so prepared myself, I have never had to do that .... yet ...... but I'm ready!

[Claudiaj]

The saga continues. I took the truck to the Chevlorlet/GMC dealer after talking with Jackson Center, which suggested firmly it was a TV issue. All systems checked out. I already know this because my son had already checked the plug with his instrument. Everything works. The dealer changed out the plug and the Check Wiring Light still continued. Fortunately, I had made an appointment with NW Airstream in Caldwell, Id, a little out of my way but they are the greatest!. They were able to squeeze me in early and Claudio checked the truck wiring AND the trailer. EVERYTHING checks out. Enough voltage to the brakes and all the lights work. Claudio stated he had seen the same issue on another GMC.Chevrlolet and the fix was to replace the manufactured installed receiver portion of the plug on the truck. It is loose and when Claudio jiggled it the lights etc were intermittent. So, next step back to the dealer. I called the dealer where I purchased the truck, Airport Chevrolet in Medford) and they can't even see me for 10 days. I explained to the service rep what I needed and that I was traveling through but all hit deaf ears.".sorry Mamm nothing available for 10 days. Next, I catch up with the salesman. The dinging and warning light continued for 1500 miles.. from Reno to Chama, NM, to Boise, ID. UGH

[Countryboy59]

You may be able to adjust or clean the terminals in the connector and fix the problem. If jiggling the plug makes the lights come on this may be the problem.

Not many techs know that the individual terminals can sometimes be removed and replaced.

[RandyNH]

A lot of times, it is just the grounding between the two vehicles. If the warning is regular enough then you can easily test it, big box store get 6' of 10awg wire and two alligator clips for the ends, clip one to truck frame other end to trailer frame, secure it well enough for test runs with enough slack for cornering.

Easy to do yourself, before dealership or mechanic had to start swapping out parts.

[Hans627]

I had a similar problem with my RAM truck when hooking up to my AS. I bought my AS as a used model. The PO had a older (about 10 years old) Ford 250 as a TV. He could hook up and the brakes worked as they should and I would hook up and it would give me the "no trailer attached" signal.

I thought it was the truck and had it throughly checked at two dealerships with no defects. I had the AS checked twice and they found nothing defective. But when I plugged the umbilical cord into the the TV, again the "no trailer attached" and no brakes.

Finally a service tech at Camping world took an interest in the issue and made it his personal challenge. Apparently there was a short (a pinched wire) on the AS that would only show when hooked up to the TV. When the pinched wire was replaced everything worked as it should. I asked why the PO had no issues and I was told that the newer TV's systems are much more sensitive. I don't know but no issues since then. Electrical issues are my achilles heel!

I'm not sure this will be helpful or not.