Town Car V8-4.6L SOHC VIN W (1999)
Headlamp Dimmer Switch: Flow of Diagnosis
1. Verify the customer's concern by operating the ignition switch and multi-function switch.
2. Visually inspect for obvious signs of mechanical and electrical damage.
Visual Inspection Chart
3. If inspection reveals an obvious concern that is readily identified, repair the concern before continuing with Inspection and Verification.
4. If the concern remains after inspection, connect the New Generation STAR (NGS) Tester to the data link connector located beneath the instrument
panel to perform Data Link Diagnostics Test. If the NGS responds with NO RESPONSE/NOT EQUIPPED for the lighting control module (LCM)
, go to Pinpoint Test A. If the Data Link Diagnostics Test is passed for the LCM module, retrieve continuous Diagnostic Trouble Codes (DTCs)
and execute Self-Test Diagnostics for the LCM module to retrieve current DTCs.
5. If the self-test is passed and no DTCs are retrieved, go to Symptom Chart to continue diagnostics.
6. If the LCM cannot be accessed by NGS, go to Pinpoint Test A.
Service Bay Diagnostic System (SBDS) may also be used to diagnose this system.
