Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test F: The Defrost System Will Not Shut Off Automatically
2005 Ford Taurus SEL, 4D SedanSECTION Pinpoint Test F: The Defrost System Will Not Shut Off Automatically
- F1 RETRIEVE DIAGNOSTIC TROUBLE CODES
- Use the recorded results from the smart junction box (SJB) self-test.
- Are any DTCs retrieved?
- Yes
: For DTC B1345 and B1347, GO to F3.
For all other DTCs, REFER to SMART JUNCTION BOX (SJB) DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- No : GO to F2.
- F2 CHECK THE SJB FOR STUCK/STICKING HEATED REAR WINDOW RELAY 1
- Disconnect: SJB Heated Rear Window Relay 1 C2021.
- Does the rear window defrost system shut OFF?
- F3 CHECK THE SJB HEATED REAR WINDOW RELAY 1
- Carry out the Rear Window Defrost Relay 1 Component Test. Refer to COMPONENT TESTING article for component testing.
- Did the relay pass the component test?
- Yes : GO to F7.
- No : INSTALL a new SJB rear window defrost relay 1. CLEAR the DTCs. REPEAT the self-test.
- F4 CHECK RELAY CENTER BOX 1 FOR STUCK/STICKING HEATED REAR WINDOW RELAY 2
- Disconnect: Relay Center Box 1 Heated Rear Window Relay 2 C1099.
- Does the rear window defrost system shut OFF?
- Yes : GO to F5.
- No : REPAIR circuit 185 (BK). CLEAR the DTCs. REPEAT the self-test.
- F5 CHECK RELAY CENTER BOX 1 HEATED REAR WINDOW RELAY 2
- Carry out the Relay Center Box 1 Rear Window Defrost Relay 2 Component Test. Refer to COMPONENT TESTING article for component testing.
- Did the relay pass the component test?
- Yes : GO to F6.
- No : INSTALL a new relay center box 1 rear window defrost relay 2. CLEAR the DTCs. REPEAT the self-test.
- F6 CHECK CIRCUIT 186 (BN/LB) FOR A SHORT TO POWER
- Key in OFF position.
- Disconnect: SJB C2280c.
- Key in ON position.
- Measure the voltage between the relay center box 1 rear window defrost relay 2 C1099 pin 86, circuit 186 (BN/LB), harness side and ground.
- Is any voltage present?
- Yes : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
- No : GO to F7
- F7 CHECK FOR CORRECT SJB OPERATION
- Disconnect all SJB connectors.
- Check for:
- corrosion
- pushed-out pins
- Connect all 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 . CLEAR the DTCs. REPEAT the SJB self-test.
- No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.