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Home >> GMC >> 1993 >> Forward Control 7.4 N >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Gauges & Instrument Panels >> Testing >> Fuel Gauge >> Gauge Is Inaccurate

Gauge Is Inaccurate

  1. Unplug fuel gauge sending unit wire. Connect one lead of gauge tester to Pink wire which goes to fuel gauge. Connect other tester to ground. Turn ignition on. Observe gauge. Adjust tester resistance dials to zero, then to 90 ohms. Allow time for gauge to respond.
  2. Gauge should indicate empty, then full. If gauge responds correctly, check fuel tank ground wire for high resistance. Repair if necessary. If ground circuit is okay, replace fuel tank sending unit.
  3. If gauge does not respond correctly, check for high resistance in Pink wire between sending unit and gauge. If Pink wire is okay, replace fuel gauge.
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