Service Trailer Brake warning

[jered6323]

2018 Sierra 1500 SLT, just past 50k miles, and started throwing a warning to Service Trailer Brake. I’ve never towed anything with a trailer brake, but want to get it fixed. How do I go about diagnosing whether it’s the module above the spare tire, or the module in the dash, or possibly something else?

[Mark Wagner]

Bumping this topic seeing if there was any info?  I had the same thing.  I took a gamble and replaced the ITBC module, and didn't fix it.  I bought a obd2 reader, and it's not showing any codes somehow.  

[mysery1]

Curious is the fault only present when towing a trailer with the 7 pin connector hooked up.

[Beer Belly]

I had mine throw the same warning, not hooked to the camper. Dealer diagnosed it was the dash Brake Control, they wanted $130 to replce it. Rock Auto, iirc, about $40. I held out on doing the replacement until yesterday when it threw the warning again (very intermittent), only took 15 minutes to replace it, easy fix.....if that is the problem, we'll see.