Pinpoint Test C: All The Locks Operate From One Switch Only

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 THE VOLTAGE TO THE INOPERATIVE DOOR LOCK CONTROL SWITCH
- Disconnect: Passenger Door Lock Control Switch C605.
- Disconnect: Driver Door Lock Control Switch C505.
- Measure the voltage between the inoperative door lock control switch C605 (passenger), or C505 (driver), pin 4, circuit 116(RD/BK), and ground.
  
  Fig 1: Measuring Voltage Between Inoperative Door Lock Control Switch C605, Or C505 Pin 4, Circuit 116(RD/BK), And Ground
  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 THE CIRCUITRY RESISTANCE
- Disconnect: Driver Door Lock Control Switch C505.
- Measure the resistance between the driver door lock control switch C505 pin 7, circuit 119 (PK/YE), harness side and ground.
  
  Fig 2: Measuring Resistance Between Driver Door Lock Control Switch C505 Pin 7 Circuit 119 Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the driver door lock control switch C505 pin 3, circuit 120 (PK/LG), and ground.
  
  Fig 3: Measuring Resistance Between Driver Door Lock Control Switch C505 Pin 3 Circuit 120 And Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
- Yes : INSTALL a new door lock control switch. REFER to DOOR LOCK CONTROL SWITCH in this article. TEST the system for normal operation.
- No : REPAIR the circuit(s) in question. TEST the system for normal operation.