How Does Battery Isolation Solenoid Wire Up to Prevent Vehicle Battery Drain

Published 12/19/2019

Question:

Hi, I have a 2017 RAM 2500 BigHorn 6.4 liter gas, and tow a large travel trailer. I want to prevent the RAMs battery from being drained by the trailer when the RAM is off, and the trailers wiring harness is plugged into the truck. Currently, I have to constantly unplug the trailer from the truck, or I will have a dead truck battery overight. It sounds like this item will do the trick, but I dont know what wires to connect it to on this particular truck. Can you advise? Thanks very much.

asked by: Dave T

Helpful Expert Reply:

The Battery Isolation Solenoid # PK5231201 is exactly what you need to deactivate your trailer wiring 12 volt circuit when your 2017 Ram 2500 is turned off. So what you need to do is cut the wire that leads to the pin in the 1:00 position of your 7-way while leaving enough room to reconnect it and then run both sides of that wire to the larger outside posts of the solenoid. Then you need to run a circuit that only sees power when the key is on to the center post of the solenoid. This is what turns the solenoid "on" and allows the voltage to travel through it. The picture I attached shows this as well.

So to find the circuit for the center pin you can use any circuit's power wire that only comes on when the vehicle is on. In the fuse box there should be a circuit labeled IGN which would be one example you could use.

expert reply by: Jameson C