Pinpoint Test A: No Communication With The Instrument Cluster

WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK THE INSTRUMENT CLUSTER POWER SUPPLY

Key in OFF position.
Disconnect: Instrument Cluster C220a and C220b.
Key in ON position.

Measure the voltage between the instrument cluster, harness side and ground, as follows:

INSTRUMENT CLUSTER CONNECTOR-PIN AND CIRCUIT REFERENCE CHART

Instrument Cluster Connector-Pin	Circuit
C220b-18	295 (LB/PK)
C220a-1	3049 (BK/LG)
C220a-7	489 (PK/BK)

Are the voltages greater than 10 volts?

Yes : GO to A2.
No : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.

A2 CHECK INSTRUMENT CLUSTER GROUND CIRCUITS 1205 (BK) AND 1203 (BK/LB)
- Key in OFF position.
- Measure the resistance between the instrument cluster C220b-11, circuit 1205 (BK), harness side and ground; and between the instrument cluster C220a-2, circuit 1203 (BK/LB), harness side and ground.
  
  Fig 1: Checking Instrument Cluster Ground Circuits 1205 (BK) And 1203 (BK/LB)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue communication diagnosis.
- No : REPAIR the circuit(s) in question. CLEAR the DTCs. REPEAT the self-test.