Courtesy/Dome Lamps Inoperative With Headlamp Switch
Possible Causes:
- Open Ground circuit.
- Courtesy Lamp Switch Output/Sense circuit open.
- Headlamp Switch.
- CTM.
CAUTION:
Always turn ignition off before disconnecting or connecting any control module connector. Failure to do so could result in damage to control module.
NOTE:
Ensure vehicle being tested has a fully charged battery. If it does not, false symptoms may occur.
NOTE:
For component location, see appropriate illustration under COMPONENT LOCATIONS
. For terminal identification, see appropriate illustration under CONNECTOR IDENTIFICATION
. For circuit and wire color identification, see WIRING DIAGRAMS
. For component removal and installation procedures, see appropriate component under REMOVAL & INSTALLATION
.
Testing:
- Turn ignition off. Disconnect Headlamp Switch harness connector. Using a 12-volt test light connected to 12 volts, probe Headlamp Switch harness connector terminal No. 9. Does test light illuminate? If yes, go to next step. If no, repair open in Ground circuit. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.
- Disconnect CTM C1 harness connector. Measure resistance between CTM C1 harness connector terminal No. 21 and Headlamp Switch harness connector terminal No. 10. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in Courtesy Lamp Switch Output/Sense circuit. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.
- Reconnect CTM C1 harness connector. Remove Headlamp Switch. Turn Courtesy Lamp Switch on. Measure resistance between Headlamp Switch terminal No. 9 and terminal No. 10 (component side). Is resistance less than 5 ohms? If yes, replace CTM. Perform BODY VERIFICATION TEST under VERIFICATION TESTS. If no, replace Headlamp Switch. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.