GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the circuit description and perform the necessary inspections?

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Go to Step 2

Go to Symptoms

2

  1. Press any of the power door lock switches to the unlock position.
  2. Disconnect the rear liftgate release motor.
  3. Use the test lamp in order to probe CKT 1306 (LT GRN) wire cavity A at the motor connector to ground.
  4. Press the liftgate release switch.

Does the test lamp light?

--

Go to Step 3

Go to Step 6

3

  1. Use a test lamp in order to probe CKT 1450 (BLK) cavity B at the rear liftgate release motor connector to CKT 1306 (LT GRN) cavity A.
  2. Press the liftgate release switch.

Does the test lamp light?

--

Go to Step 5

Go to Step 4

4

Repair the open in CKT 1450 (BLK) between the rear liftgate release motor and G403.

Is the repair complete?

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Go to Step 19

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5

  1. Replace the rear liftgate release motor.
  2. Press the liftgate release switch.

Is the repair complete?

--

Go to Step 19

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6

  1. Use a test lamp in order to backprobe CKT 1306 (LT GRN) wire cavity C3 at the liftgate lock/unlock relay to ground.
  2. Press the liftgate release switch.

Does the test lamp light?

--

Go to Step 7

Go to Step 8

7

Repair the open in CKT 1306 (LT GRN) between the rear liftgate release motor and G403.

Is the repair complete?

--

Go to Step 19

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8

  1. Use a test lamp in order to backprobe CKT 1305 (PPL) wire cavity B2 at the liftgate lock/unlock relay to ground.
  2. Press the liftgate release switch.

Does the test lamp light?

--

Go to Step 12

Go to Step 9

9

  1. Use a test lamp in order to backprobe CKT 1305 (PPL) wire cavity C of the liftgate lock/unlock release switch connector to ground.
  2. Press the Liftgate release switch.

Does the test lamp light?

--

Go to Step 10

Go to Step 11

10

Repair the open in CKT 1305 (PPL) between the lock/unlock release switch and the liftgate lock/unlock relay.

Is the repair complete?

--

Go to Step 19

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11

Replace the liftgate lock/unlock release switch. Refer to Liftgate Lock Cylinder Replacement .

Does the liftgate release switch operate properly?

--

Go to Step 19

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12

  1. Disconnect the liftgate lock/unlock relay.
  2. Use a DMM in order to probe CKT 1450 (BLK) wire cavity B1 at the liftgate lock/unlock relay connector to ground.

Is there continuity?

--

Go to Step 14

Go to Step 13

13

Repair the open in CKT 1450 (BLK) between the liftgate lock/unlock relay and G403.

Is the repair complete?

--

Go to Step 19

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14

  1. Connect a test lamp between CKT 295 (GRY) wire cavity A1 of the liftgate lock/unlock relay and ground.
  2. Press any of the power door lock switches to the LOCK position.

Does the test lamp light?

--

Go to Step 16

Go to Step 15

15

Repair an open in CKT 295 (GRY) between the liftgate lock/unlock relay and splice S335.

Is the repair complete?

--

Go to Step 19

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16

  1. Connect a test lamp between CKT 294 (TAN) cavity C1 of the liftgate lock/unlock relay and ground.
  2. Press any of the power door lock switches to the unlock position.

Does the test lamp light?

--

Go to Step 17

Go to Step 18

17

Replace the liftgate lock/unlock relay.

Is the repair complete?

--

Go to Step 19

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18

Repair the open in CKT 294 (TAN) between the liftgate lock/unlock relay and splice S334.

Is the repair complete?

--

Go to Step 19

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19

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2