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Home >> Buick >> 1987 >> Electra Base >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Testing >> Engagement Switch Test

Engagement Switch Test

  1. Turn ignition on. Turn engagement switch to "OFF" position. Measure voltage at the control module connector pin A (circuit No. 397). Connect other end of voltmeter to a known good ground.
  2. If measured voltage is zero volts, go to step 3). If measured voltage is 12 volts, disconnect cruise switch connector and measure voltage at terminal A (harness side) to ground. If the measured voltage is 12 volts, engagement switch is malfunctioning and should be replaced. If measured voltage is zero volts, check for blown fuse or open in wiring circuit No. 39.
  3. If voltage measured in step 1) was zero volts, place engagement switch slider in "ON" position. Measure voltage from control module connector pin A (circuit No. 397) to ground. If 12 volts are present, engagement switch is okay.
  4. If voltage measured is zero volts, disconnect cruise switch connector and measure voltage at terminal B (switch side) and ground. If measured voltage is 12 volts, find open in circuit No. 397 between terminal B of connector and pin A of control module.
  5. If voltage measured in step 4) was zero volts, measure voltage between terminal A (harness side) of connector and ground. If measured voltage is 12 volts, engagement switch is malfunctioning and must be replaced.
  6. If voltage measured in step 5) was zero volts, check fuse. If fuse is okay, check for open in wiring between fuse and switch. If fuse is blown, replace. If fuse does not blow again, road test vehicle. If fuse does blow again, check all branches of circuit No. 39 from fuse to find short to ground.
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