How to Turn Off 12-V Power Feed to 7-Way Trailer Connector on Vehicle When Ignition is Shut Off

Updated 06/20/2020 | Published 06/19/2020

Products Featured in This Question

10 Gauge Wire - Blue Primary - Per Foot

(108)

$1.65

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

(13)

$35.41

Question:

If I leave my trailer connected to the truck while it is not running it drains the battery. I placed a meter on the 7 point connection and it appears the 12 volt pin is hot at all times. How does one fix this without tearing out the dashboard?

asked by: Ryan

Expert Reply:

This is very easily fixed. Simply install a battery isolation solenoid, part # PK5231201. This will disable that 12-Volt feed when the ignition is shut off. The solenoid is usually mounted in the engine compartment.

The product description overview video I've linked will run you through how to wire the solenoid. The terminal on either side is used for the incoming and outgoing power it doesn't matter which terminal is used for which and the center terminal is used to an ignition switched circuit. The radio circuit is often used, because it typically powers down when the ignition is off.

expert reply by: Mike L