3. Cable - The cable is used to transfer the high volt-
age
produced
by
the
ballast
module
to
the
lamp/igniter.
DIAGNOSIS AND TESTING
HIGH INTENSITY DISCHARGE HEADLAMPS
The High Intensity Discharge (HID) headlamps are supplied B+ voltage and ground, the same as normal halogen
low beam lamps. The low beam system is different from there forward. The ballast module is mounted to the bottom
of the headlamp unit. The ballast module has internal circuit protection to prevent module damage in case of an
open or shorted circuit. The module has overcharge and undercharge circuit protection. If either is sensed, the mod-
ule will not illuminate the headlamps for that key cycle or until the fault is corrected. Recycle the ignition and head-
lamp switch if both headlamps do not illuminate. Before determining the headlamp assembly is faulty, check the
connector at the headlamp and check if there is voltage coming from the IPM pin providing the power to the respec-
tive headlamp. If the module senses a short or open circuit condition, it will not operate the lamp/igniter.
WARNING: The headlamp unit must be removed to perform these tests (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HEADLAMP UNIT - REMOVAL). Failure to do so could result in personal injury or
death.
1. Inspect lamp for a burned out lamp. If lamp is burned out it will appear black or smoky, similar to a normal
halogen bulb. If lamp looks OK, go to Step 2.
2. Check for B+ battery voltage at the connector going into the ballast module. Refer to Wiring Diagrams for con-
nector location. If battery voltage and a good ground are present, go to Step 3. If B+ voltage and a good ground
are not present, refer to Wiring Diagrams for circuit and connector locations to find short or open circuit.
3. Plug in a known good ballast module and check for lamp operation. If lamp lights, replace ballast module. If lamp
still fails to light, replace igniter assembly.
8L - 94
LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION
LX