Test Description

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The numbers below refer to the step numbers on the diagnostic table.

3. At least two of the DTCs must be set as current DTC to ensure correct diagnosis. If only one DTC is present then the answer is No.
5. Tests for the proper operation of the circuit in the low voltage range.
6. Tests for the proper operation of the circuit in the high voltage range. If the jumper fuse opens when you perform this test, the circuit is shorted to ground.
7. Tests for a short to voltage in the 5-volt reference circuit.
8. Tests for a high resistance or for an open in the low reference circuit.
9. This step tests for an open on the low reference circuit that is common to all of the actuators. Choose the easiest HVAC door actuator that set a DTC to start the diagnosis.
10. Disconnecting each actuator, one at a time, isolates the disconnected actuators signal circuit from the 5-volt reference circuit that is common to all the actuators.

Fig 1: DTC B0414, B0424, Or B3770 Diagnosis Procedure (Step 1 To 9)
Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC B0414, B0424, Or B3770 Diagnosis Procedure (Step 10 To 19)
Courtesy of GENERAL MOTORS CORP.

Fig 3: DTC B0414, B0424, Or B3770 Diagnosis Procedure (Step 20 To 22)
Courtesy of GENERAL MOTORS CORP.