Power & Ground - Test Procedure
- Turn headlights off. Unplug connectors C1 (10 pins) and C2 (16 pins) from lamp control module, located at right of steering column, behind instrument panel. See Fig 1
or Fig 2
. Set dimmer switch to low beam position. Set shift lever to Park position. Turn ignition on.
Courtesy of GENERAL MOTORS CORP.
Courtesy of GENERAL MOTORS CORP.
- Check for battery voltage at connector C1 terminal "K" (Pink wire). If battery voltage does not exist, check Pink wire for open or short to ground.
- Check for battery voltage at connector C1 terminal "H" (Orange wire). If battery voltage does not exist, check Orange wire for open or short to ground.
- Check for battery voltage between connector C1 terminals "H" (Orange wire) and "E" (Black/White wire). If battery voltage does not exist, check Black/White wire for open.
- Check for battery voltage between connector C1 terminals "H" (Orange wire) and "F" (Black/White wire). If battery voltage does not exist, check Black/White wire for open.
- Check for battery voltage between connector C1 terminal "G" (Black wire) and ground. If battery voltage does not exist, check Black wire for open. If wire and connections are okay, replace headlight switch and go to RESISTANCE TEST. If vehicle is equipped with DRL, continue with steps 7) through 10).
- Set headlight switch to PARK position. Check for battery voltage between connector C1 terminal "C" (Brown wire) and ground. If battery voltage does not exist, check Brown wire for open.
- Check for battery voltage between connector C2 terminal B8 (Light Green/Black wire) and ground. If battery voltage does not exist, check Light Green/Black or Pink/Black wire for open circuit. Also check park/neutral switch. See WIRING DIAGRAMS
in this article.
- Set shift lever to Drive position. Check for voltage between connector C2 terminal B8 (Light Green/Black wire) and ground. If voltage exists, check Light Green/Black wire for short to voltage. Also check park/neutral switch for short or misalignment.
- Connect fused jumper between connector C1 terminals "K" (Pink wire) and "D" (Gray wire). If low beam headlights do not come on at reduced intensity, check Gray or Tan wires for open. Check DRL resistor, located at left front corner of engine compartment. If wires, connections, and resistor are okay, go to RESISTANCE TEST.