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How to install a Master Disconnect Relocation Battery Switch on your Mustang

Installation Time

3 hours

American Muscle
Shop Parts in this Guide



1. Determine the mounting location for the switch following your sanctioning guidelines.

2. Drill a 25/32” hole through the panel you are mounting through to accept the switch-mounting stem.

3. Remove the switch handle loosing the screw in the center. Remove the first nut and lock washer. Pass the switch through the hole in the panel and secure in place using the lockwasher and nut. Re-attach the switch handle.

4. Apply the ON/OFF Label.


1. Disconnect the positive and negative battery terminal. Make sure the switch in the off position.

2. Connect a battery cable from the starter or starter solenoid to one of the 1/2” switch terminals. The battery cable should be a minimum of 2-gauge wire.

3. Connect a jumper wire from the alternator output terminal to one of the 3/16” terminals. Use a minimum of 10-gauge wire for this connector (maximum current 20 amps).

4. Connect a jumper wire to remaining 1/2” terminal to the remaining 3/16” terminal.

5. Connect the positive terminal on the battery to the 1/2” stud on the switch that has the jumper wire mounted to it. Use a minimum of 2-gauge wire for the connection.

6. Reconnect the positive and negative battery terminals; making certain the negative side of the battery is fastened to a clean ground, preferably the engine block.

7. To check the wiring: turn switch on, start the vehicle, and turn switch off. The vehicle should stop running. If not, re-check your wiring to the diagram below.

This guide applies to Vehicle years: 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 and Submodels: Boss 302, Foxbody, Mach 1, V6, Bullitt, Cobra, GT, GT500, EcoBoost, GT350