GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you review the power door system Description and Operation?

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Go to Step 2

Go to Diagnostic Starting Point - Doors

2

Close all doors, and remove the ignition key from the ignition cylinder.

Does the power door locks system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Place the dome lamp switch in its door ajar state.
  2. With all doors closed, observe the dome lamps and the door ajar indicator.

Is the dome lamp illuminated or the door ajar indicator ON?

--

Go to Door Ajar Indicator Malfunction

Go to Step 4

4

Is the door lock system completely inoperative from both doors?

--

Go to Step 5

Go to Power Door Locks Inoperative - One Door or Switch

5

Is the 25 amp DOOR fuse open?

--

Go to Step 13

Go to Step 6

6

Measure the voltage between the master switch lock signal circuit to the multifunction alarm module at the master switch harness connector and a good ground.

Does the voltage measure near the specified value?

0.180-0.250  volts

Go to Step 7

Go to Step 11

7

Measure the voltage between the master switch unlock signal circuit to the multifunction alarm module at the master switch harness connector and a good ground.

Does the voltage measure near the specified value?

0.180-0.250 volts

Go to Step 8

Go to Step 12

8

Measure the voltage between the driver door key cylinder lock signal circuit and a good ground.

Does the voltage measure near the specified value?

0.180-0.250 volts

Go to Step 9

Go to Step 15

9

Measure the voltage between the driver door key cylinder switch unlock signal circuit and a good ground.

Does the voltage measure near the specified value?

0.180-0.250 volts

Go to Step 10

Go to Step 16

10

Measure the voltage between the passenger door key cylinder switch unlock signal circuit and a good ground.

Does the voltage measure near the specified value?

0.180-0.250 volts

Go to Step 13

Go to Step 16

11

Test the door lock switch lock signal circuit for an open or short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

12

Test the appropriate door lock switch unlock signal circuit for an open or short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

13

Test the appropriate door lock actuator lock control circuit for an open or short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 14

14

Test the appropriate door lock actuator unlock control circuit for an open or short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

15

Test the appropriate key cylinder switch lock signal circuit for a short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

16

Test the appropriate key cylinder switch unlock signal circuit for an open or short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 17

17

Inspect for poor connections at the harness connector of the multifunction alarm module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 18

18

Replace the multifunction alarm module. Refer to Multifunction Alarm Module Replacement in Instrument Panel, Gages and Console.

Did you complete the replacement?

--

Go to Step 19

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19

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2