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Home >> Chevrolet >> 1990 >> APV >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Fuel System (Diesel) >> Inhibit Switch (Black Cap)
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Inhibit Switch (Black Cap)

  1. Remove connector from inhibit switch when engine temperature is below 100°F (38°C). Inhibit switch is located in water crossover near front of engine. Set ohmmeter on low range. Test across switch terminals. Switch should be closed (a reading of less than 1.0 ohm on meter.)
  2. Test terminals to ground with a test light or ohmmeter on high range. Light should be off. Meter should show greater than 1.0 megohm. Replace switch if results are not as specified.
  3. Disconnect plug from switch terminals when engine is above 125°F (52°C). Change ohmmeter setting to highest scale or use a self-powered test light. Test across switch terminals. Test from each terminal to ground. Switch should be open (test light off or high ohm reading of greater than 1.0 megohm on meter). Replace switch if it is closed. When installing replacement switch, tighten to 17 ft. lbs. (23 N.m).
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