Check Fuse - Turn ignition off. Check condition of central junction box fuse No. 21 (40-amp). If fuse is okay, go to next step. If fuse is not okay, replace fuse. Retest system operation. If fuse fails again, check Violet/Blue wire and Violet/White wire for short to ground. Repair as necessary and retest system operation.
Check Violet/Blue Wire For Open - Ensure ignition is off. Remove and disconnect driver door master window switch. Using an ohmmeter, check resistance between central junction box fuse No. 21 (40-amp) output terminal (left terminal) and driver door master window switch 4-pin connector C74b terminal No. 2 (Violet/Blue wire). See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/Blue wire and retest system operation.
Check Black Wire For Open - Using an ohmmeter, check resistance between ground and driver door master window switch connector C74b terminal No. 3 (Black wire). If resistance is less than 5 ohms, replace driver door master window switch and retest system operation. If resistance is 5 ohms or more, repair open in Black wire between driver door master window switch and ground. Retest system operation.

Fig 1: Identifying Driver Door Master Window Switch Connector C74b Terminals (Harness Side)

Courtesy of FORD MOTOR CO.

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.

Safety Warning

Test A: All Power Windows Inoperative