Wipers and Electric Windows both failed?

ANDYANDREWS

MEMBER
2004 FORD RANGER
2.3L
4 CYL
4WD
AUTOMATIC
89,000 MILES

Wipers and Electric Windows both stopped working and seemingly simultaneously. I was told it was likely a problem with the Smart Junction Box located to the right of the passenger leg space. I took it out, cleaned it carefully with an electric contact cleaner, removed all oxidation and any sign of corrosion, replaced one of the relays that looked sketchy, replaced the 30-amp fuse labeled as wipers, reinstalled the unit and - no change. Now I’m thinking I was looking at the wrong fuse box. Any guidance would be sincerely appreciated. Thanks.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

In addition to being an electrical distribution center for several vehicle systems, the smart junction box (SJB) is a multi-function electronic module, with inputs and outputs for several electrical systems including the PW and the wipers.

The SJB constantly monitors the circuits of the electronic systems it controls. If the SJB detects an open, a short to ground, or a short to power in the driver-side power window circuits, for example, it will set a diagnostic trouble code (DTC). DTCs can be retrieved with a diagnostic tool. This requires scanning the can-bus circuits. CAN stands for controller area network.

All the different modules are tied together via a few wires. This type of scan will retrieve codes from all modules. In this case, I suspect you will find codes related to the two items you are having trouble with.

Here is a link that explains how to scan the can-bus:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

I attached the wiring schematics for both the power windows and the wipers. Confirm the fuses I highlighted are good and that there is power to and from them.

Here is a link that you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Also, the SJB is on the passenger side behind the kick panel. See pics 5 and 6.

Let me know if this helps, what you find, or if you have other questions. Note: If the power supply is present at the SJB and it doesn't respond, the SJB will likely need replaced.

Let me know.,

Joe

See pics below.

Images (Click to make bigger)