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System Testing

WARNING: This page is about a different car, the 1992 Lexus SC 400, 1992 Lexus SC 300, 1992 Lexus LS 400, and 1992 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ensure all in-line fuses or circuit breakers are okay. Turn ignition and defogger switches to ON position. Rear glass and mirrors should feel warm after a few minutes.
  2. If glass is not warm, use a test light or voltmeter to check for battery voltage at grid feed wire. If voltage is not correct, check wiring harness, control switch and relay. If mirrors are not warm, check mirror defogger. See MIRROR DEFOGGER  under TESTING.
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