warning message

[golfer1]

Ok folks, we are finally hitting the road the day after tomorrow. Had a medical problem with the dear wife. All is ok now.
My problem is this. We got the monty out of storage yesterday. All went well. Today however I got a warning message the read Service trailor braking system. I have a 2008 Silverado 2500 with 6600 miles. Only towed less than 20 miles. Any ideas what this message may mean and should I get it serviced beofre I hit the road. I tend to lean on the side of caution. Anyone have this message and what does it mean? If not enough detail let me know and I will elaborate.
Thanks you folks are the best.

[Countryfolks]

After a short search it appears it could be loose/dirty ABS connections, damaged wire in ABS system, or an ABS module problem. Apparently it could be connected to recalculation of tire size using a tuner also.

[dwstockman]

While towing, I've had the same message come up but only after driving in wet conditions. The message has always went off if I unplugging the trailer connector, spray it with WD-40 and reconnect.

[sreigle]

Mike, I don't have an answer for you but wanted to say we're glad to hear your wife is fine now. And that we enjoyed lunch with you awhile back.