Pinpoint Test B: The Instrument Cluster (Ic) Illumination Is Inoperative

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

B1 CHECK CIRCUIT 29S-LA31 (OG/BU) FOR AN OPEN
- Disconnect: IC C2220
- With the parking lamps on, rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the IC connector C2220-29, circuit 29S-LA31 (OG/BU), harness side and ground.
- Is the voltage greater than 10 volts?
1. YES : Go to B2.
2. NO : REPAIR the circuit. TEST the system for normal operation.
B2 CHECK CIRCUIT 91-GG14 (BK/OG) FOR AN OPEN
- Turn the parking lamps off.
- Measure the resistance between the IC C2220-30, circuit 91-GG14 (BK/OG), harness side and ground.
- Is the resistance less than 5 ohms?
1. YES : Go to B3.
2. NO : REPAIR the circuit. TEST the system for normal operation.
B3 CHECK FOR CORRECT IC OPERATION
- Disconnect the IC connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the IC connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new IC. REFER to INSTRUMENT CLUSTER article. TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.