Module Display Not Illuminated, Too Dim, Or Totally Black
- Place ignition switch in "RUN" position. Check for back lighting of fuel computer/system scanner module. If other module is okay, replace burned out bulb(s). If other module is too dim or not okay, go to next step.
- Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION in this article. Measure resistance between pin "3C" (terminal No. 3, connector C) and pin "11B". See INSTRUMENT CLUSTER PIN CONNECTOR IDENTIFICATION illustration. Reading should be less than one ohm resistance. If resistance is more than one ohm, repair illumination ground circuit. If resistance is okay, go to next step.
- Place ignition switch in "RUN" position. Check display for back lighting. Turn headlights on. Move dimmer switch to maximum brightness. Check display for back lighting.
- If module does not light in "RUN" position or with headlights on, go to next step. If module is illuminated in "RUN" position but not with headlights on, go to step 6). If module is illuminated with headlights on but not in "RUN" position, go to next step. If module is too dim, go to step 7).
- Measure voltage at pin "C8" (LCD illumination line). If reading is more than 10 volts, replace speedometer module. If reading is less than 10 volts, repair illumination circuits, fuses, or replace headlight switch.
- Turn headlight switch on. Move dimmer switch to maximum brightness. Measure voltage at pin "C8" (LCD illumination line). If reading is more than 10 volts, replace speedometer module. If reading is less than 10 volts, repair illumination circuits, fuses, or replace headlight switch.
- Place ignition switch in "RUN" position. Check for burned out bulbs. If necessary, replace burned out bulbs. If bulbs are okay, check for correct bulb type. If bulbs are of correct type, go back to step 5).