Power Mirror Position Sensor Test

Disconnect electrical connector from power mirror motor. Connect three 1.5-volt dry cell batteries together in series. See Fig 1. Connect dry cell positive lead to terminal No. 5 and negative lead to terminal No. 8. Connect voltmeter between terminals No. 6 and 8.
While watching voltmeter, apply 12 volts across terminals No. 1 and 2, reversing polarity as necessary to move mirror in both directions. As mirror moves, voltage should gradually and smoothly change from 0.0-0.9 volt to 2.8-5.0 volts.
Disconnect voltmeter and 12-volt battery from motor connector terminals (leave dry cell assembly connected). Connect voltmeter between terminals No. 7 and 8. Apply 12 volts across terminals No. 1 and 3 (reverse polarity as necessary). If voltage is not as specified in step 2), replace power mirror assembly.

Fig 1: Testing Power Mirror Position Sensor (LS400)