Pinpoint Test I: One Turn Signal Lamp Is Inoperative/Always On

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

I1 CHECK THE STOPLAMPS
- Key in OFF position.
- Make sure the multifunction switch is in the neutral position.
- Observe the stoplamps while applying and releasing the brake pedal.
- Do the stoplamps operate correctly?
- Yes : GO to I2.
- No : REFER to STOPLAMPS to diagnose the stoplamps.
I2 DETERMINE THE CONDITION
- Key in ON position.
- While observing the turn lamps, place the multifunction switch to the LH and then RH turn positions.
- Is the individual turn lamp always on?
- Yes : GO to I3.
- No : GO to I4.
I3 CHECK THE VOLTAGE SUPPLY CIRCUIT FOR SHORT TO POWER
- Key in OFF position.
- Disconnect: Multifunction Switch C202a.
- Key in ON position.
- Does the turn signal lamp continue to illuminate?
- Yes : For the RH front turn lamp, REPAIR circuit 2 (WH/LB). TEST the system for normal operation.
  For the LH front turn lamp, REPAIR circuit 9 (LG/WH). TEST the system for normal operation.
- No : INSTALL a new multifunction switch.
REFER to STEERING COLUMN SWITCHES . TEST the system for normal operation.
I4 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Key in OFF position.
- Disconnect: Inoperative Turn Lamp.
- Measure the resistance between the inoperative front turn lamp connector pin 1, circuit 57 (BK) and ground.
  
  Fig 1: Measuring Resistance Between Inoperative Front Turn Lamp Connector Pin 1 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to I5.
- No : REPAIR the circuit. TEST the system for normal operation.
I5 CHECK CIRCUIT 2 (WH/LB) OR CIRCUIT 3 (LG/WH) FOR AN OPEN
- Disconnect: Multifunction Switch C202a.
- Measure the resistance between the RH turn lamp C1043 pin 3, circuit 2 (WH/LB), harness side and the multifunction switch C202a pin 2, circuit 2 (WH/LB), harness side; or between the LH turn lamp C1023 pin 3, circuit 3 (LG/WH), harness side and the multifunction switch C202a pin 3, circuit 3 (LG/WH), harness side
  
  Fig 2: Measuring Resistance Between RH Turn Lamp Pin 3 And Multifunction Switch Pin 2
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new multifunction switch. REFER to STEERING COLUMN SWITCHES . TEST the system for normal operation.
- No : REPAIR the circuit in question. TEST the system for normal operation.