Urgent - Stuck at Rest Stop - Trailer wiring problem

[Brit2]

I am hoping someone out there can help. We are in Massachusetts and headed to Florida towing a sailboat trailer. Onstar was useless with technical issues. So I am hoping someone watching this forum can help.
When the lights are off on the car, all the trailer lights work. When the lights are on on the car, only the trailer tongue running lights work. No brakes or turn directionals on the Trailer. I am sure this is a simple fix, but onstar can't help us. It is a 2012 Chevy Suburban.
Does Anyone out there have a clue? I have two kids who need to get to a sailing race on Friday.

Thanks,
Brit2

 

[Aquila99Burb]

Tried replacing the trailer plug/adapter? I had a similar situation towing with an Range Rover. I had bad connections. Contact cleaner helped get rid of a lot of the gunk on the connectors - then we found out the connector / adapter was faulty and had to replace.

If you are still at a truck stop, they might have replacements. Good luck.

 

[VanGo]

very possible that it's a pinched wire(s) somewhere. Herd to troubleshoot over the internet. Good luck and good sailing! I'm in drydock