7 way plug issue w/ 'Service Trailer Brake' message

SophieP · June 8, 2018

Our trailer has an electric jack so we plugged it in to raise & lower the jack, but had trouble getting a connection. After a few minutes of wiggling it around, it connected. It resulted in a 'Service Trailer Brake' message, but we hadn't even moved the trailer. We tried cleaning the plug and outlet and applied dielectric grease just in case it was moisture, but it did the same thing. A trip to the dealer today to see if the truck had a loose connection was a waste of time since they found nothing wrong. We have a 2017 2500HD with less than 5000 miles on it and our trailer is less than a year old. We're going camping in a few days......any ideas??? HELP!!!

redwngr · June 8, 2018

A little emery cloth and some contact cleaner.

Whenever I've had that type message it's been dirty connectors on truck or trailer or both.

Di-electric grease is non-conductive.

http://www.tech-faq.com/dielectric-grease.html

SophieP · June 8, 2018

9 minutes ago, redwngr said:

A little emery cloth and some contact cleaner.

Whenever I've had that type message it's been dirty connectors on truck or trailer or both.

Di-electric grease is non-conductive.

http://www.tech-faq.com/dielectric-grease.html

Thanks redwings, will give that a try tomorrow!

swathdiver · June 8, 2018

Did the dealership tell you what the internal codes are? If that message comes up, there are codes telling why.

SophieP · June 9, 2018

No, they didn’t....just said they didn’t find anything wrong!

jhplak325 · June 9, 2018

I would look at the 7 plug on the trailer, GM recommends using a Pollak plug on the trailer side.

My camper had a Bargman molded 7 plug and I couldn’t get a good connection, replaced with a Pollak and haven’t had a problem since.

GM TSB -

SophieP · June 9, 2018

29 minutes ago, jhplak325 said:

I would look at the 7 plug on the trailer, GM recommends using a Pollak plug on the trailer side.

My camper had a Bargman molded 7 plug and I couldn’t get a good connection, replaced with a Pollak and haven’t had a problem since.

GM TSB -

Thanks.....will look into that!

SophieP · June 9, 2018

23 hours ago, redwngr said:

A little emery cloth and some contact cleaner.

Whenever I've had that type message it's been dirty connectors on truck or trailer or both.

Di-electric grease is non-conductive.

http://www.tech-faq.com/dielectric-grease.html

That did the trick!!!!! It took a while to clean out all the dielectric grease since my husband was overly generous, then the emery cloth & contact cleaner and it works perfectly!!!! THANK YOU!!!!!! (happy dance)

redwngr · June 10, 2018

1 hour ago, SophieP said:

That did the trick!!!!! It took a while to clean out all the dielectric grease since my husband was overly generous, then the emery cloth & contact cleaner and it works perfectly!!!! THANK YOU!!!!!! (happy dance)

Glad to hear that solved the problem!

B284 · June 12, 2018

Well here it is everyone.... I have spent more money today trying to fix this problem only to learn that the DEALERS will check your equipment and find nothing wrong. This is because the device used to control our electric trailer brakes can't recognize what type of brakes we have on a trailer.

As you read the link below, if you chose to click on it, you will find this is not covered under any warranty and is left for the owners to determine how to remedy the problem. They have suggested several methods to fix the problem however they will not take ownership for the poor design nor have they chose to recall it.

Happy reading. If you have found a good way to fix this, please do tell.

https://gm.oemdtc.com/TSB/SB-10081241-2280.pdf

If this link above doesn't work go to google and search GM Service Bulletin No: 5509. This was dated Jun - 2016

pogrelis97 · June 19, 2018

On ‎6‎/‎9‎/‎2018 at 5:58 AM, jhplak325 said:

I would look at the 7 plug on the trailer, GM recommends using a Pollak plug on the trailer side.

My camper had a Bargman molded 7 plug and I couldn’t get a good connection, replaced with a Pollak and haven’t had a problem since.

GM TSB -

Thanks, just ordered one for my gooseneck I cant get the brakes to work on. But they work fine behind my dads 2006.

azsheepdog · July 11, 2018

I have found that my truck does this if it running when I plug in. If my truck is off and I plug in and then start up it finds the trailer and all is happy with the world. The same trailer did not do this with my 10.

redwngr · July 26, 2018

On 7/11/2018 at 1:25 PM, azsheepdog said:

I have found that my truck does this if it running when I plug in. If my truck is off and I plug in and then start up it finds the trailer and all is happy with the world. The same trailer did not do this with my 10.

I've always been able to plug in with the truck running and not had trouble with not being recognized -- except when a connector needed cleaning.

A bunch of different GM pickups with factory brake controllers hooked to a bunch of different utility, bulk material and flat deck trailers.

All trailers were electric brakes on Dexter axles -- none had electric over hydraulic, but as I understand it the brake controllers are supposed to detect and work with those as well.