Check Trailer Wiring Message

[Ziggie]

Hello,

 

Driving from work my 2008 GMC Sierra Votex MAX I was hammered with messges "Check Trailer Wiring".

I was not even pulling trailer since last fall.

I have factory brake controller, and fifth wheel connector in the box was spliced to the bumper trailer connector by the hitch installers before I even got the truck new, by the installers hired by the dealer.

Any idea what that message is indicating?, Should I pull the 40 A fuse for the trailer power?

 

Thanks.

 

Ziggie

[fraiolib]

how bout checking the wiring and making sure all the wires are connected and also check for corrosion

[Ziggie]

how bout checking the wiring and making sure all the wires are connected and also check for corrosion

Yes, I will do that, I just checked, all seem to be ok on both connectors, and since I do not use trailer, it is possible that there is short being developed due to moisture. Will chek all tomorow.

[Ziggie]

So the problem is fixed.

The bumper mounted receptacle was full of water, on the back where the truck's trailer wiring wires plugs into that receptacle, seal must be bad or was not plugged all the way, there is rubber o-ring seal, yet it was full of water.

Winter is just ending here and it is very wet here.

I dried it up, filled with white nonconductive grease and plugged in, no warnings anymore.

It would appear that somehow the truck sensed the current leak, perhaps to the break controller and gave me the that message. I have the battery voltage there for charging the trailer battery if I use the trailer, so this must be the reason.

One more thing I noticed that when I was getting the "check trailer wireing massages", the alternator voltage went up, something like 15 volts or so. Normaly the voltage will be up for a while and then after the battery is charged to 100%, the voltage drops below 14 volts. This is called "Voltage Management' with is in new vehicles. When truck was new, I fricked out first time I saw the voltage gage go down at 200 km or so, I called the dealer and they explained this to me.

 

The question still remain, how the system knew there was a problem with the wiring.

I do not have schematics for this truck yet, it is too new and Hynes manual is not out yet, but I will try to get the schematics and figure out how the system knew that. Like I said, I think the brake controller sensed some votage on the "brake outpout" line and gave an alarm, due to low resitance in the receptacle from B+ to breake signal. No trailer was connceted for at least of half of a year. Preety smart if you ask me.

 

Ziggie

[8.1HD/ALLISON]

+1 the trailer control module monitors the connection. The water in the connector must have made contact across some of the wires making it think you had a trailer connected.