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© 2002 Directed Electronics, Inc. Vista, CA
The best places to find the door pin switch wire are:
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At the pin switch: When testing at the pin switch, check the wire to ensure that it “sees” all the doors. Often,
the passenger switch will cover all the doors even if the driver’s switch will not.
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At the dome light: This may not be your best choice if the vehicle has delayed domelight supervision, but it
will work in many Hondas, or any vehicle with completely diode-isolated pin switches.
Once you have determined the wire color, the easiest place to connect to the wire is often at the kick panel, at
the windshield pillar, or in the running board. When an easy location is not available, running a wire to the dome-
light itself is often the best solution.
How to find a door pin switch trigger wire with your multimeter:
1. Set to DCV or DC voltage (12V or 20V is fine).
2. In most Fords, fasten the (-) probe of the meter to chassis ground. In most other cars, fasten the (+) probe
of your meter to (+)12V constant.
3. Probe the wire you suspect of being the door trigger wire. If the meter reads (+)12V when any door
is opened, you have found a trigger wire.
NOTE:
Make sure the wire you use “sees” all the doors! Some newer GM vehicles lack standard-type
pin switches. The dome light in these vehicles is turned on when the door handle is lifted. These
usually have a blue/white or white wire coming out of the door into the kick panel which will
provide a (-) trigger for all doors. Some GM vehicles (some Cavaliers, Grand Ams, etc.) have a yellow
wire coming out of the door which provides a (+) door trigger.
The starter wire provides 12V directly to the starter or to a relay controlling the starter. In some vehicles, it is
necessary to power a cold start circuit. A cold start circuit will test exactly like a starter circuit, but it does not
control the starter. Instead, the cold start circuit is used to prime the fuel injection system for starting when the
vehicle is cold.
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 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.
finding the starter wire
finding the door pin switch circuit
