12-Volt Accessory Power Pin in 7-way on 2009 Silverado Only Showing 5 Volts

Question:

I recently had a Brake Controller installed on my 09 Silverado by an RV shop. They told me i wasnt getting the full 12volts from the stud on the under hood fuse box to pin4 of the 7way trailer plug to charge the trailer battery, i was only getting just over 5volts. What can cause the in voltage?

asked by: Vinny

Expert Reply:

The most likely cause of the voltage drop you're seeing on that 12-volt accessory circuit is a damaged wire or loose connection.

The simplest way to solve the problem is to bypass the existing circuit and run your own. You can use a length of 10 gauge wire like part # 10-1-1 and a 40 amp circuit breaker like part # 9510 to make a run from the positive battery terminal to the 12-volt accessory power pin on the 7-way.

Keep in mind that the 12-volt circuit is NOT capable of charging a fully depleted trailer mounted battery. It will provide a maintenance charge, but to charge the battery fully you'll need shore power and a battery charger like the CTEK # CTEK56353.

expert reply by: Mike L