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3. Start and run the vehicle.
4. Probe the wire you suspect of being the tachometer wire with the red probe of the meter.
5. If this is the correct wire the meter will read between 1V and 6V.
In diesel vehicles it is necessary to interface with the wire that turns on the WAIT TO START light in the dash-
board. This wire illuminates the bulb until the vehicle’s glow plugs are properly heated. When the light goes out
the vehicle can be started. This wire is always available at the connector leading to the bulb in the dashboard.
It can also be found at the Engine Control Module (ECM) in many vehicles.
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wiirree::
1. Set your multimeter to DCV or DC voltage (12 or 20V is fine).
2. Attach the (+) probe of the meter to (+)12V.
3. Probe the wire that you suspect leads to the bulb with the (-) probe of the meter.
4. Turn the ignition switch to the ON position.
5. If the meter indicates 12 volts until the light goes out you have isolated the correct wire and the wire's polar-
ity is negative (ground while the bulb is on).
6. If the meter reads zero volts until the light goes out and then reads 12 volts, you have isolated the correct
wire and the wire's polarity is positive.
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 avail-
able in the kick panel or running board.
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OTTEE:: 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 the dimmer setting.
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meetteerr::
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
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