Pinpoint Test C: The Climate Control Illumination Is Inoperative

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK CIRCUIT 19 (LB/RD) FOR AN OPEN
- Key in OFF position.
- Disconnect: Climate Control C228a (EATC) or C294b (Manual).
- Place the headlamp switch in the ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the climate control 228a pin 14 (EATC) or C294b pin 1 (manual), circuit 19 (LB/RD), harness side and ground.
  
  Fig 1: Checking Circuit 19 (LB/RD) For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to C2.
- No : REPAIR the circuit. TEST the system for normal operation.
C2 CHECK CIRCUIT 676 (PK/OG) (EATC) OR 57 (BK) (MANUAL) FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Measure the resistance between the climate control C228a pin 2, circuit 676 (PK/OG) (EATC) or C294b pin 2, circuit 57 (BK) (manual), harness side and ground.
  
  Fig 2: Checking Circuit 676 (PK/OG) (EATC) Or 57 (BK) (Manual) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a climate control assembly. REFER to CONTROL COMPONENTS .
- No : REPAIR the circuit. TEST the system for normal operation.