Normal Operation

WARNING: This page is about a different car, the 2007 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

Under normal operation, when any wiper mode except OFF is selected, the multi-function switch provides a combination of grounds to the smart junction box (SJB) through circuits CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG) and CRW15 (BN/WH). The SJB interprets this ground combination to determine the desired wiper mode.

When the SJB commands the wipers ON, ground is provided to the run/park relay coil through circuit RRW24 (GN/VT). When the run/park relay is energized, voltage is sent from the run/park relay to the high/low relay through circuit CRW25 (BU/GY). Voltage is passed through the high/low relay to the wiper motor through circuit CRW10 (BU/GN) (low) or CRW08 (VT/OG) (high). The SJB monitors the park switch status through circuit CRW09 (BN/BU).

Possible Causes

A short to voltage in circuit CRW25 (BU/GY), CRW08 (VT/OG), CRW10 (BU/GN) or CRW09 (BN/BU)
A short to ground in circuit CRW17 (GN/VT), CRW18 (VT/WH), CRW19 (BU/OG), RRW24 (GN/VT) or CRW15 (BN/WH)
Wiper run/park relay
Multi-function switch
Smart junction box (SJB)