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© 2003 Directed Electronics, Inc. Vista, CA
How to find the starter wire with your multimeter:
1. Set to DCV or DC voltage (12V or 20V is fine).
2. Attach the (-) probe of the meter to chassis ground.
3. Probe the wire you suspect of being the starter wire. The steering
column is an excellent place to find this wire. Remember you do not
need to interrupt the starter at the same point you test it. Hiding your
optional starter kill relay and connections is always recommended.
4. Turn the ignition key switch to the start position. Make sure the car is
not in gear! If your meter reads (+)12V, go to the next step. If it doesn’t, probe another wire.
5. Cut the wire you suspect of being the starter wire.
6. Attempt to start the car. If the starter engages, reconnect it and go back to Step 3. If the starter does not
turn over, you have the right wire.
Most vehicles use a (+) brake light circuit. The (+) brake light wire is often found near the brake pedal. The same
wire can often be accessed in the kick panel or running board.
How to find a (+) brake light wire with your multimeter:
1. Set to DCV or DC voltage (12V or 20V is fine).
2. Attach the (-) probe of the meter to chassis ground.
3. Probe the wire you suspect of being the brake light wire.
4. Press the brake pedal. If your meter shows (+)12V, release the brake pedal and make sure it goes back to
zero.
5. If it does return to zero, this is the correct brake wire.
An accessory/heater wire will show +12V when the key is in the accessory and run positions. It will not show
+12V during the cranking cycle. There will often be more than one accessory wire in the ignition harness. The
correct accessory wire will power the vehicle's climate control system. Some vehicles may have separate wires for
the blower motor and the air conditioning compressor. In such cases, it will be necessary to add a relay to power
the second accessory wire.
finding the accessory/heater wire
finding a (+) brake light wire
