Troubleshooting Trailer 7-Way Not Working on 2012 Ram 3500 with Chassis Mount Tiger Coach

Question:

The 7 pin tow plug is dead with no power to any terminals. All 7 wires from the 7 pin plug are spliced into the factory wiring harness at the rear. Separately wired into the harness the coach tail lights, brake lights, running lights and backup lights all work. What is the common link that would stop all function in this harness for towing but still allow the harness to function for the coach.

asked by: Ben N

Expert Reply:

The good news is that we know the issue is isolated to your 2012 Ram 3500 and even even better, the only place you are having issues is after where your coach wiring splices off.

With that in mind you simply need to check the 7-Way connector and wiring at the rear of your pickup. Check the connector for any corrosion or debris that could be causing connectivity issues. If that looks clear then inspect the wiring from the back of the connector all the way to where your coach lighting is spliced in. Chances are there has been some damage to the wires and it is either exposed or bent somewhere which is causing the loss of power.

To replace your wiring you have 2 options. You can either use the a tee like the Hopkins # 41157 or you can splice in different wiring with the Hopkins # HM40975-11998. Typically the tee connection is used to add a 7-Way to the bed of a pickup but you should be able to use it this way as well. If you go with the splicing method then I have also attached a diagram showing what wires from the Hopkins harness connect to which functions from your pickup.

If your wiring looks good then you may want to take your pickup to a shop and have them take a look at it.

expert reply by: Jon G