© 2001 Directed Electronics, Inc. Vista, CA
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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.
To test and determine the polarity of this wire:
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.
primary harness (H1) wiring diagram
______
______
______
______
______
______
______
______
LIGHT BLUE
(-) 200 mA DOOR UNLOCK OUTPUT
LIGHT GREEN
(-) 200 mA DOOR LOCK OUTPUT
GRAY/BLACK
(-) WAIT-TO-START INPUT
WHITE
(-) 200 mA LIGHT FLASH OUTPUT
YELLOW
(+) IGNITION (OUTPUT TO OPTIONAL SECURITY SYSTEM)
LIGHT GREEN/BLACK
(-) FACTORY DISARM/SPECIAL ACCESSORY
WHITE/BLUE
(-) REMOTE START ACTIVATION INPUT
BLACK
(-) CHASSIS GROUND INPUT
H1/1
H1/2
H1/3
H1/4
H1/5
H1/6
H1/7
H1/8
finding the wait-to-start bulb wire for diesels