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Home >> Cadillac >> 1989 >> Allante F7/ME9 >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Computer Module >> Diagnostic Tests >> DTC B120: Twilight Delay Switch Pot Circuit >> Test Procedure

Test Procedure

  1. BCM data value BD43 displays twilight delay time. The normal range is 5-95%.
  2. Checks to see if the open or grounded circuit reading is due to the circuit or the switch. If the open or grounded circuit reading changes from a short to voltage reading after jumping the switch assembly terminals, the BCM and wiring are okay.
  3. Measuring between circuits No. 705 (5 volts) and No. 271 will determine if circuit No. 271 is open or shorted to ground.
  4. Checks to see if the short to voltage circuit reading is due to the circuit or the switch assembly. If a short to voltage reading changes to an open circuit reading after disconnecting the switch assembly, the BCM and wiring are okay.
Fig 1: DTC B120: Twilight Delay Switch Pot Flow Chart
G00103581Courtesy of GENERAL MOTORS CORP.
Fig 2: DTC B120: Twilight Delay Pot Circuit Flow Chart Circuit
G00103580Courtesy of GENERAL MOTORS CORP.
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