Display Does Not Dim or Brighten With Dimmer
Display does not dim or brighten with dimmerNOTE: Check the vehicle battery condition first.
1. Turn the ignition switch to ON (II).
2. Turn the combination light switch ON and OFF to see if the symptom can be duplicated.
Is the symptom duplicated?
YES - Go to step 3.
NO - Operation is normal.
3. Turn the combination light switch OFF.
4. Operate the illumination control dial.
Is it normal?
YES - Operation is normal.
NO - Go to step 5.
5. Disconnect and check audio unit connector A (17P) for a loose or a poor connection, then reconnect audio unit connector A (17P) and recheck the symptom.
NOTE: Eject the CD before removing the audio unit to prevent damaging the CD player's load mechanism.
Does the problem still appear?
YES - Go to step 6.
NO - Operation is normal.
6. Measure the voltage between audio unit connector A (17P) No. 1 and No. 10 terminals. Turn the instrument panel brightness control knob (at the gauge control module) to see if the voltage changes.
Does the voltage change from 25 V in the fully dim position to battery voltage in the full bright position?
YES - Substitute a known-good audio unit, and recheck. If the symptom/indication goes away, replace the original audio unit.
NO - Go to step 7.
7. Check for continuity between audio unit connector A (17P) No. 1 terminal and gauge control module connector A (20P) No. 15 terminal.
Is there continuity?
YES - Go to gauge control module input test, Component Tests and General Diagnostics and test circuit A15 and A9.
NO - Repair open in the wire between the gauge control module and the audio unit.