Randy Platz

Hello everyone. I have a 2021 GMC 2500HD Duramax AT4. New Years eve treaded my truck to a touchless car wash. Drove home and parked in the garage (where it always parks) It sat until Monday. Upon start up in came up with a 3 messages, Check Trailer Right turn lamp, than Check Trailer Left turn lamp, then check Trail brake lamps. However there is no trailer connected. I thought maybe water in the 7 pin plug. Nope clear and dry, just a little dielectric. Check the trucks turn signals and they blink very fast light a burned out bulb. Checked all the fuses, all good. Checked under the truck and all connection look good. Thinking is the trailer lamp lighting control module. Though of going to the dealer, but of course the truck just turned 38,000. Has anyone else ran into this? I did search online and found 1 You-tube video where a guy cut one open all corroded. I do live in Wisconsin and land of salt. When the truck was new I had the under side coated with rubberized rust proofing.

I just Ordered a 2020 AT4 and wne t shopping for a cap, and was told it would block the camera. Really bumbed. Hopefuly GM will come out with a relocate kit of some kind.