Ford wipers Wiring diagram
Diagnose and fix with Ford Wipers wiring diagram
The Ford wiper control system on late model vehicles is completely different than anything you’re used to in the past. Examine the Ford wipers wiring diagram below. First, notice thathe wiper speed switch is now called a multi-function switch (MFS). It does not actually switch power to the wiper motor. It just acts a signaling device to tell the Smart Junction Box (SJB) what action you’d like it to take. In this case, the Smart Junction Box performs the same functions as a Body Control Module used in other makes and models. So you’ll have to check reference voltages coming into the MFS based on the position of the switch. Then you’ll have to check the grounds provided by the SJB the run to the control coils on the Park/Run and Hi/Low relays.
The wiring diagram shows how Ford wipers work
The SJB provides a reference voltage to the MFS. The voltage flows through resistors built into the MFS and then to ground. The SJB measure the voltage drop and based on the remaining voltage, determines what setting the driver has requested. The SJB then applies a ground to the appropriate relays which then provide power to the wiper motor and washer motor.
What to check first when Ford wipers don’t work
As you can see by the Ford wiper wiring diagram, the system uses several fuses:
• 30A fuse for the wiper motor relays and wiper motor
• 15A fuse for the washer motor relay and washer motor
• 10A fuse for the low current board in the SJC to receive the washer signal from the MFS and provide ground to the washer relay. (the low current circuit board is in the SJC)
Check those fuses first
Then check for power at the relays. Follow the Ford wiper wiring diagram and check for power at the relay contacts and control coil. Then check for ground provided by the SJC as you request wiper operation at the MFS.
Check for power at the wiper motor
Finally, check for good ground conditions at the MFS, SJC, Wiper motor and washer motor.
©, 2018 Rick MuscoplatPosted on by Rick Muscoplat