On-Vehicle Inspection

1. Turn the rheostat knob OFF, and check that there is no continuity between terminals 5 and 4 (rheostat knob turned fully counterclockwise).
2. Gradually turn rheostat knob from the dark side to bright side, and check that there is continuity between terminals 5 and 4 (rheostat knob turned clockwise).

Fig 1: Inspecting Light Control Rheostat

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If operation is not as specified, replace the rheostat.