What Battery Post to Disconnect on 2020 GMC Sierra 1500 With Roadmaster Automatic Battery Disconnect

Updated 05/11/2022 | Published 05/10/2022

Question:

Owners manual says to disconnect neg. Terminal to flat tow a 2020 gmc your disconnect switch you sell according to information is set up to disconnect positive terminal, Does it matter to vehicle which is disconnected

asked by: Larry

Expert Reply:

You do need to disconnect the positive terminal on your 2020 GMC Sierra 1500 when using the Roadmaster Automatic Battery Disconnect with Switch # RM-766.

The reason why is that disconnecting the negative battery cable, the truck's chassis ground is removed, which means the wiring and brake system lose the ground at your GMC and would need to be grounded via the motorhome chassis. This would be very problematic so you will want to disconnect the positive terminal when using the Roadmaster Automatic Battery Disconnect with Switch # RM-766.

expert reply by: Kyle S