Pinpoint Test V: The Low Coolant Level Indicator Is Never/Always On: Testing

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

V1 CARRY OUT THE INSTRUMENT CLUSTER INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE DIAGNOSTIC TOOL
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command.
- Select the instrument cluster warning lamps and chime active command. Trigger the all lamps active command on and off. Observe the low washer fluid indicator.
- Does the low coolant level indicator illuminate when triggered on and turn off when triggered off?
- Yes : GO to V2.
- No : GO to V10.
V2 RETRIEVE THE RECORDED SMART JUNCTION BOX (SJB) DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND SELF-TESTS
- Check for recorded SJB DTCs from the continuous and on-demand self-tests.
- Are any DTCs recorded?
- Yes : If DTC B2678 is retrieved, GO to V3.
- No : GO to V9.
V3 CHECK THE SJB COOLANT FLUID LEVEL PID
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: SJB Coolant Fluid level PID.
  Select the SJB coolant input switch status and monitor the coolant level PID.
- Does the PID read LOW?
- Yes : GO to V4.
- No ; GO to V9.
V4 CHECK CIRCUIT 794 (LB) FOR A SHORT TO GROUND
- Disconnect: Low Coolant Level Switch C1069.
- Enter the following diagnostic mode on the scan tool: SJB Coolant Fluid Level PID.
  Select the SJB coolant input switch status and monitor the coolant level PID.
- Does the PID read OK?
- Yes : INSTALL a new low coolant level switch. REFER to ENGINE COOLING . CLEAR the DTCs. REPEAT the self-test.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
V5 CHECK THE COOLANT LEVEL SWITCH
- Disconnect: Low Coolant Level Switch C1069.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: SJB PID.
  Select the SJB coolant input switch status and monitor the coolant level PID.
- Connect a fused (10A) jumper wire between the low coolant level switch C1069-2, circuit 794 (LB), harness side and ground.
  
  Fig 1: Connecting Fused (10A) Jumper Wire Between Low Coolant Level Switch C1069-2 And Ground
  Courtesy of FORD MOTOR CO.
- Monitor the SJB coolant level PID.
- Does the PID read OK then change to LOW with the fused jumper connected?
- Yes : GO to V7.
- No : REMOVE the jumper wire. GO to V6.
V6 CHECK CIRCUIT 794 (LB) FOR AN OPEN
- Key in OFF position.
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-13, circuit 794 (LB), harness side and the low coolant level switch C1069-2, circuit 794 (LB), harness side.
  
  Fig 2: Measuring Resistance Between SJB C2280A-13 And Low Coolant Level Switch C1069-2
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to V9.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
V7 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
- Measure the resistance between the low coolant level switch C1069-1, circuit 1205 (BK), harness side and ground.
  
  Fig 3: Measuring Resistance Between Low Coolant Level Switch C1069-1 And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to V8.
- No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
V8 CHECK THE LOW COOLANT LEVEL SWITCH
- Measure the resistance between the low coolant level switch C1069 pin 2, component side and the low coolant level switch C1069 pin 1, component side, with the reservoir empty, and with the reservoir filled
  
  Fig 4: Measuring Resistance Between Low Coolant Level Switch C1069 Pin 2 And Low Coolant Level Switch C1069 Pin 1
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms with the reservoir empty, and greater than 10,000 ohms with the reservoir filled?
- Yes : GO to V9.
- No : INSTALL a new low coolant level switch. REFER to ENGINE COOLING . CLEAR the DTCs. REPEAT the self-test.
V9 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
V10 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect the instrument cluster connector.
- Check for:
  - corrosion
  - pushed-out pins
- Connect the instrument cluster connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new instrument cluster. REFER to INSTRUMENT CLUSTER . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.