• Test switch is used with an amp meter to isolate parasitic amperage draws on all GM vehicles or any vehicle with a side- or top-post battery
• This tool attaches between the negative battery lead and the battery, then the vehicle road is tested
• The next step is to connect an amp meter to each side of the switch, thereby allowing all available current to pass through the meter
• Fuses are then removed one at a time until the circuit source of the parasitic draw is located
• Similar to J-38758