Diagnosis - Interior Lamps: Dimming

TROUBLESHOOTING HINTS:
1. Check the condition of the ILLUM fuse. If the fuse is open, locate and repair the source of the overload. Replace the fuse.
2. Check for the proper installation of any aftermarket electronic equipment which may effect the integrity of other systems.
3. Check for a broken (or partially broken) wire inside of the insulation which could cause a system malfunction but prove good in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded. Monitor for a voltage drop with the system operational (under load).
4. If the IP lamps do not dim when using the IP dimmer switch, check the GRY (1220) wire for a short to voltage. If OK, replace the headlamp switch.
5. If the IP lamps dim erratically when using the IP dimmer switch, check the IP dimmer switch for a poor connection. If OK, replace the IP dimmer switch.
6. If one or more of the IP lamps does not light, check the GRY (1220) wire for voltage at the inoperative lamp. If voltage exists, repair the open in the BLK (328), the BLK (451), or the BLK (1050) wire.




IP LAMPS DO NOT LIGHT

CIRCUIT OPERATION
With the headlamp in the park or headlamp position, voltage is supplied to the IP dimmer switch. Voltage passes through the dimmer switch to the IP fuse block fuse 5 to the illumination lamps. The intensity of the illumination lamps is controlled via the dimmer switch. The rheostat in the dimmer switch varies voltage to the lamps, which also varies lamp intensity. The lamps are permanently grounded so they light when ever the headlamp switch is turned on.