Troubleshooting Battery Drain After Installing Replacement 7-Way Trailer Connector on 2004 Tahoe

Question:

I installed a new electrical outlet to my new hitch and my battery is going dead within two days what could be the problem

asked by: Dave

Expert Reply:

If your Tahoe's battery is suddenly discharging after installation of a new 7-way trailer connector such as the Hopkins # HM40975 then you'll want to check the wiring for the short that is likely to be causing this.

The issue could be pretty much anywhere on the vehicle, from the trailer connector itself to the harness that connects to it, or anywhere along the wiring leading to the battery. There could be an issue with the 12V power wire that has rubbed on the frame or other parts of the vehicle and worn off the insulation which would cause a dead short. There could be a corrosion problem within the connectors that is causing the 12V auxiliary power circuit to be bridged to another circuit. If you find a bad wire simply replace it with # 10-1-1; if you find corrosion apply a aerosol electrical contact cleaner like Caig De-Oxit.

If you cannot find the issue you can bypass that circuit with a new 12V power circuit. You will need a 40-amp circuit breaker # PK54540, enough 10-gauge wire # 10-1-1 to reach from the trailer connector up to the battery in the engine compartment, rings terminals # DW05705-1 and a butt connector # 05732-2. These items will allow you to run a completely new power circuit from the battery to the 7-way trailer socket which will completely bypass the existing wiring.

The new power wire will need to be spliced to the power wire at the 7-way at the back of the vehicle. If you refer to the linked photo of a 7-way you'll note that the 12V power circuit from the battery should be connected to the contact at the 1:00 position.