I have a 2001 k3500 with the factory towing setup (they probably all have it). I have no vehicle power to the trailer wiring connector for the LH turn signal or brake light. I've pulled the plug off the back of the connector and that plug has no power for those items either. Any suggestions about where to begin troubleshooting? Or am I just stuck tracing the wires back with diagram? Hate to let the stealership have my money.