Ford wipers won’t turn off

Ford wipers won’t turn off — diagnose and fix

If your Ford wipers won’t turn off, there are a few possibilities. Like all late model vehicles, the wiper switch doesn’t actually switch power to the wiper motor like in the old days. It’s just a signal input to the body control module (BCM) telling it you’re requesting wiper operation.

How late model Ford wiper systems work

The multifunction wiper switch contains multiple resistors that drop the voltage based on the position of the switch. The switch is the input for the following functions:

Windshield wash
Off
AUTO 1/INT 1
AUTO 2/INT 2
AUTO 3/INT 3
AUTO 4/INT 4
AUTO 5/INT 5
Low wiper speed
High wiper speed

The multifunction switch connects to the steering column control module (SCCM) which communicates with the BCM via the high speed CAN bus. The wiper relay in the battery junction box is energized when the ignition is on. When the driver commands a wiper operation the digital command routes through the SCCM to the BCM which provides a ground to the wiper relay control coil mounted in the battery junction box.

If the Ford wipers won’t turn off

1) First check the operation of the wiper relay in the battery junction box to see if the relay contacts are stuck in the ON position. Try tapping the relay with a screwdriver handle to vibrate the contacts. Or, swap the relay with another relay of the same size.

2) If the wiper still operates, use a scan tool with live data to monitor the status of the multifunction switch. If the BCM is seeing a wiper request from the multifunction switch, but the actual wiper switch is turned off, replace the multi function wiper switch because the problem is inside the switch.
©, 2023 Rick Muscoplat