Join Date: Oct 2017
Location: NE Washington
Thanked 127 Times in 125 Posts
Here's a link to the Newbies Guide for your new truck. It contains a Factory Service Manual that may help your to troubleshoot your electrical issues.
Have you tested all functions on the 7 pin plug with a test light to make sure everything is working on the truck? That would isolate the problem to the truck vs the trailer. Bad trailer grounds and corroded sockets, etc., can raise havoc with trailer lighting. I had a similar issue with my 05. Everything worked except the left turn signal signal on the trailer. After much troubleshooting I ended up having to replace the TIPM as it turned out to be a non-serviceable bad relay.
05 Ram 3500, SLT Bighorn, SB QC, Dynamic Stage 3 48RE, triple disc, billet input, S&B CAI, FASS Titanium, Smarty Jr., New stock Bosch injectors, Edge CTS, Hushpower/Magnaflow 4 inch, FTE Resonator, Bilstein 5100's, Redhead Steering, Truxedo, Linex