How to Disconnect the Battery on a 2021 GMC Sierra with Diesel Engine

Updated 02/25/2022 | Published 02/24/2022

Products Featured in This Question

Roadmaster Battery Disconnect for Towed Vehicle w/ Flat Tow Brake System - Gas Only

(371)

$227.78

Deka Lead Quick-Disconnect Battery Terminal - Universal Polarity

(34)

$29.73

Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Way to 6-Way Coiled Adapter Cord

(3183)

$179.84

Question:

Which kit will allow me to get the vehicle set up to flat tow behind my motor coach? I have seen different kits and need to make sure I have what is correct.

asked by: Rick H

Helpful Expert Reply:

You are correct that the Roadmaster Automatic Battery Disconnect # RM-766 cannot be used with diesel engine vehicles like your GMC Sierra. The issue is the high compression ratio of diesels that cause the engine to surge up to 10 times that of gas engines, which can lead to failure on the solenoid.

What you can use instead is an alternate-style of battery disconnect like the Deka # DW05312 (uses a knob to attach and detach) or the Epicord # 277-000096. The Epicord # 277-000096 includes a switch you could mount inside the cab which would still allow you to easily disconnect the battery each time you're ready to tow your Sierra.

expert reply by: Scott S

Rick H.

2/24/2022

Which kit will allow me to get the vehicle set up to flat tow behind my motor coach? I have seen different kits and need to make sure I have what is correct.

Scott S.

2/25/2022

The tow bar wiring that I recommend for your 2021 GMC Sierra 1500 is the Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit # RM-15267. This wiring kit allows you to use your GMC Sierra 1500's tail lights and wiring system while preventing feedback from your RV. This wiring kit is made in the USA and features a limited lifetime warranty.