Ohmmeter Procedure

With yellow and white (Brown-Matador) wires disconnected from switch, connect ohmmeter across switch terminals. With switch in "OFF" position, ohmmeter should read infinity. With ohmmeter leads reversed, ohmmeter should read zero (or nearly zero). With switch depressed and held in "ON" position, ohmmeter should read zero.

Fig 1: American Motors Heated Rear Window Wiring Diagram

Courtesy of AMERICAN MOTORS/RENAULT CORP.