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© 1998 Directed Electronics, Inc. Vista, CA
N438 7/98
Finding a (+) parking light wire
The (+) parking light wire is often found near the switch. Many cars have the switch built into the turn signal lever,
and in these cars the parking light wire can be found in the steering column. The same wire is often available in the
kick panel or running board.
NOTE: Many Toyotas, as well as many other Asian vehicles, send a (-) signal from the switch to a relay.
The relay then sends 12V(+) to the bulbs. Whenever you have difficulty finding a (+) parking light wire near
the switch, simply test the wires at any switch or control panel which is lit by the instrument panel lighting.
Remember, you need a (+) parking light wire that does not vary with dimmer setting.
How to find a (+) parking light flash 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 parking light wire. Usually,
the area near the headlight/parking light switch is an excellent
area to start, as is the kick panel.
4. Turn on the parking lights. If your meter shows (+)12V, turn off the
parking lights and make
sure it goes back to zero.
5. If it does return to zero, turn the parking lights back on and, using the dash light dimmer control,
turn the brightness of the dash lights up and down. If the meter changes more than a volt when
using the dimmer, look for another wire. If it stays relatively close to (+)12V, you have found your
parking light wire.
Finding the door pin switch circuit
The best places to find the door switch wire are:
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.
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 domelight
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. If 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 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.
