Hoping to get some help with the trailer parking light circuit on a 2018 GMC 2500 HD Duramax. No power on the parking light circuit on the 7 pin. Lights on the trailer are good - they run fine with 12v applied independent of the 7 pin. In the under hood fuse box, I checked #15 fuse (trailer parking lamps) - it's good but there is no power to the fuse. So checked relay #63 (trailer parking lamps). The relay tests good, but I don't believe it is getting power either.
I read that other GM trucks have issues with a control module for the trailer lighting circuit. I also read that there is a Technical Service Bulletin on similar issues, but I don't think it applies to this truck. Is there a trailer lighting control module for this truck? I don't know if they relate, but just in an effort to do anything I could think of, I checked several body control module fuses in the left and right interior fuse boxes - they all looked good.
Not sure what to do or check next. Any suggestions would be appreciated. Thank you!!
I read that other GM trucks have issues with a control module for the trailer lighting circuit. I also read that there is a Technical Service Bulletin on similar issues, but I don't think it applies to this truck. Is there a trailer lighting control module for this truck? I don't know if they relate, but just in an effort to do anything I could think of, I checked several body control module fuses in the left and right interior fuse boxes - they all looked good.
Not sure what to do or check next. Any suggestions would be appreciated. Thank you!!