GM Service Manual Online
For 1990-2009 cars only

Power Seat Does Not Tilt Forward (LH and RH)

Step

Action

Value(s)

Yes

No

DEFINITION: Upward or downward controls are inoperative for the front vertical motor. Horizontal and rear tilt motors operate normally. Either driver's side or passenger's side seat.

1

Were you sent here from the Power Seat System Diagnostic System Check?

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Go to Step 2

Go to Power Seats System Check

2

  1. Disconnect the LH or RH seat adjuster switch connector.
  2. Connect a jumper wire from:
  3. •  LEFT SIDE = The seat adjuster switch connector terminal 26 to ground.
    • RIGHT SIDE = The seat adjuster switch connector terminal 1 to ground.

Does the seat motor move?

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Go to Step 3

Go to Step 5

3

Connect the jumper wire from:

    • LEFT SIDE = The seat adjuster switch connector terminal 1 to ground.
    • RIGHT SIDE = The seat adjuster switch connector terminal 26 to ground.

Does the seat motor move?

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Go to Step 4

Go to Step 7

4

Replace the RH or LH seat adjuster switch. Refer to Power Seat Switch Replacement .

Is the repair complete?

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Go to Power Seats System Check

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5

  1. Disconnect the RH or LH seat relay center connector C1.
  2. Use a DMM to measure CKT 1518 for continuity between the seat relay center connector C1 terminal 16 and the seat adjuster switch connector:
  3. • LEFT SIDE = Terminal 26.
    • RIGHT SIDE = Terminal 1.

Is CKT 1518 continuous between these two connectors?

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Go to Step 9

Go to Step 6

6

Locate and repair an open or a high resistance in CKT 1518.

Is the repair complete?

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Go to Power Seats System Check

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7

  1. Disconnect the RH or LH seat relay center connector C1.
  2. Use a DMM to measure CKT 1520 for continuity between the seat relay center connector C1 terminal 17 and the seat adjuster switch connector:
  3. • LEFT SIDE = Terminal 1.
    • RIGHT SIDE = Terminal 26.

Is CKT 1520 continuous between these two connectors?

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Go to Step 9

Go to Step 8

8

Locate and repair an open or a high resistance in CKT 1520.

Is the repair complete?

--

Go to Power Seats System Check

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9

  1. Disconnect the RH or LH seat relay center connector C2 and C3.
  2. Using two jumper wires, perform the following test:
  3. • Connect a jumper wire between battery power and the seat relay center connector C3 terminal C.
    • Connect a second jumper wire between ground and the seat relay center connector C2 terminal E.
  4. Now reverse the jumper wires as follows:
  5. • Connect the jumper wire between battery power and the seat relay center connector C2 terminal E.
    • Connect the second jumper wire between ground and the seat relay center connector C3 terminal C.

Does the front vertical motor operate in both directions during each of these conditions?

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Go to Step 11

Go to Step 10

10

  1. Disconnect the RH or LH lower seat motor connector C1.
  2. Use a DMM to measure CKT 287 for continuity between the seat relay center connector C3 terminal C and the seat motor connector C1 terminal D.

Is CKT 287 continuous between these two connectors?

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Go to Step 12

Go to Step 13

11

Replace the RH or LH seat relay center.

Is the repair complete?

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Go to Power Seats System Check

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12

Locate and repair an open or a high resistance in CKT 287.

Is the repair complete?

--

Go to Power Seats System Check

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13

Use a DMM to measure CKT 286 for continuity between the seat relay center connector C2 terminal E and the seat motor connector C1 terminal C.

Is CKT 286 continuous between these two connectors?

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Go to Step 14

Go to Step 15

14

Locate and repair an open or a high resistance in CKT 286.

Is the repair complete?

--

Go to Power Seats System Check

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15

Check carefully for any binding of the front vertical seat motor and linkage. If OK, replace the RH or LH front vertical seat motor. Refer to Front Seat Adjuster Motor Replacement .

Is the repair complete?

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Go to Power Seats System Check

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