Trailer wiring warning

deltabravo wrote:

bobndot wrote:
If need be you could ask , if GM uses a scan tool to retrieve the codes from the DIC .

The DIC doesn't store the codes, the ECM/PCM stores them.

yes o.k. tnx. i meant , if the codes are showing on the DIC , then a scan tool might be able to retrieve them.

A very common problem, which I've posted about before is that some brands of RV trailer cords have a plug on them that isn't manufactured to the exact specs / industry standard, therefore they fit a bit loose in the OEM truck plug, which is usually a POLLAK brand plug.

I had the same problem, and a cargo trailer dealer I frequent told me about it so I changed the pigtail on my enclosed trailer, and that solved the problem. THe trailer plug fits the truck receptacle nice and snug now. That was 2 years ago and I haven't received the "check trailer wiring" on the DIC again.

bobndot wrote:
If need be you could ask , if GM uses a scan tool to retrieve the codes from the DIC .

The DIC doesn't store the codes, the ECM/PCM stores them.

Put some grease in the connector. It keeps the water out, and the contacts from corroding.

"Dielectric grease" for the hoity-toity, although any common grease including wheel bearing grease is dielectric at 12 VDC, so no need to go searching for nirvana. I use Super-Lube silicone grease, only because I keep a tube of it in the toolkit, and it's clear - meaning cleaner than wheel bearing grease - but that's a convenience not a necessity.

There are much better products to spray in those trailer connectors (plugs and receptacles) than WD-40 and silicone. A branded electrical connector spray works well. Spray it heavily, let it dry, and use the hawkeye-08 in-and-out method above to mechanically clean the contacts. Do it twice, or more if the contacts are really cruddy. DON'T use a knife or other sharp edge or sandpaper to clean the contacts, you'll just remove the thin copper coating on the contacts. Once you know the contacts are clean, a light coating of dielectric grease should take care of your problems for some time.

WD-40 would be OK to use if the connectors show evidence of moisture. That is what the purpose of WD-40 is. (WD-40 = Water Displacement formula number 40. I guess the first 39 formulas weren't as good.) Then use the contact cleaner to get that stuff out of there.

Had the problem on my 2011 GMC once, pulled over and put the connector in and out a few times, then made sure it was fully seated. Now when I hook up, I make sure to do the in and out a few times before leaving it fully seated with the cover locking it in place. Mine seems to be tight so perhaps I did not get it seated all the way the time I had problems.

Had the same issue last year. Cleaned the plug from trailer and the receptacle on truck with contact cleaner and then sprayed them with silicon spray. No issues ever since.

I always squirt some WD40 into the 7-pin socket before hooking up. Blows out all of the dirt and debris I guess...

Its probably better to use some of the dielectric grease compound but I always seem to have a can of WD40 and Duct Tape in my glove box haha...

Your truck electronics has see a minimum DC current being drawn when hooked up to keep that alarm from showing up on your screen.

Roy Ken

I have also seen problem with the ground connection between the trailer and tow vehicle cause intermittent problems like this. If the ground wire itself is bad then the only common grounding point is the hitch or spring bars. Those don't provide a good constant ground connection.

Yep, connection at the plug. I had the same thing occur on my Silverado and everything I found said to clean the bumper plug and trailer plug. Cleaned them up and have not had the message again so far. I keep mine lubed with battery terminal grease now. WD is an option too.