GM Service Manual Online
For 1990-2009 cars only

Power Seat Does Not Move Forward/Rearward w/o Memory Seats

Step

Action

Yes

No

Schematic Reference: Power Seats Schematics

Important: This table assumes that all mechanical linkage and drivers are free from obstruction and not binding. This also assumes that all other directions are operational.

1

Did you review the Power Seats System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Power Seats System Description and Operation

2

Operate the Power Seat System.

Does the system operate normally?

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

Go to Step 3

3

  1. Disconnect the Horizontal motor.
  2. Connect a test lamp between the Horizontal motor control circuits.
  3. Operate the power seat switch to the forward and rearward positions.

Did the test lamp illuminate for each switch position?

Go to Step 6

Go to Step 4

4

Test the control circuits of the Horizontal motor for a open or short to ground. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the power seat switch. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

6

Inspect for poor connections at the harness connector of the Horizontal motor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Replace the Horizontal motor. Refer to Front Seat Adjuster Motor Replacement .

Did you complete the replacement?

Go to Step 9

--

8

Replace the power seat switch. Refer to Power Seat Switch Replacement .

Did you complete the replacement?

Go to Step 9

--

9

Operate the system to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Power Seat Does Not Move Forward/Rearward With Memory Seats

Test Descriptions

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

  1. In order to conserve battery power, the memory Seat Module enters a sleep mode when ever the unit has not been active for 16 seconds. To wake the memory seat module again from a sleep mode, the switch must be activated .

  1. In order to conserve battery power, the memory Seat Module enters a sleep mode when ever the unit has not been active for 16 seconds. To wake the memory seat module again from a sleep mode, the switch must be activated .

  1. In order to conserve battery power, the memory Seat Module enters a sleep mode when ever the unit has not been active for 16 seconds. To wake the memory seat module again from a sleep mode, the switch must be activated .

Step

Action

Value(s)

Yes

No

Schematic Reference: Memory Seats Schematics Power Seats Schematics

Important: This table assumes that all mechanical linkage and drivers are free from obstruction and not binding. This table also assumes that all other directions are operational.

1

Did you review the power seats system Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Power Seats System Description and Operation

2

Operate the power seat in all direction.

Does the system operate normally?

--

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

Go to Step 3

3

Does the seat move for approximately 2 seconds and stop in both horizontal-forward and rearward directions?

--

Go to Step 4

Go to Step 7

4

    •  Disconnect the horizontal motor position sensor harness at the motor.
    •  Activate the seat in any direction.
    •  Measure the voltage from horizontal motor position sensor voltage reference circuit to a good ground.

Does the voltage measured near the specified value?

5 V

Go to Step 5

Go to Step 13

5

    • Activate the horizontal power seat switch in both forward and rearward directions.
    • Measure the voltage from the horizontal seat motor position sensor signal circuit to a good ground.

Does the voltage measured near the specified value?

5 V

Go to Step 6

Go to Step 14

6

    • Activate the horizontal power seat switch in both forward and rearward directions.
    • Measure the voltage between the horizontal motor position sensor voltage reference and the horizontal motor position sensor low reference.

Does the voltage measured near the specified value?

5 V

Go to Step 18

Go to Step 15

7

    •  Back probe the power seat horizontal forward switch signal at the memory seat module, with a test lamp connected to a good ground.
    • Operate the power seat switch to move the seat in horizontal forward direction while observing the test lamp.

Did the test lamp illuminate?

--

Go to Step 8

Go to Step 10

8

    • Back probe the power seat horizontal rearward switch signal at the memory seat module, with a test lamp connected to a good ground.
    • Operate the power seat switch to move the seat in horizontal rearward direction while observing the test lamp.

Did the test lamp illuminate?

--

Go to Step 9

Go to Step 11

9

    • Disconnect the horizontal motor harness connector at the horizontal motor.
    • Connect a test lamp between the horizontal motor control circuits.
    • Operate the power seat switch to the forward and rearward direction.

Did the test lamp illuminate for both switch positions?

--

Go to Step 17

Go to Step 12

10

Test the power seat horizontal forward switch signal circuit to the memory seat module for 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 23

Go to Step 16

11

Test the power seat horizontal rearward switch signal circuit to the memory seat module for 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 23

Go to Step 16

12

Test horizontal motor control circuit(s) between the harness connector and memory seat module for open or short to ground. Refer to Circuit Testing and Wiring Repairs and in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 23

Go to Step 19

13

Test horizontal motor position sensor voltage reference circuit for 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 23

Go to Step 19

14

Test horizontal motor position sensor signal circuit for open, short to ground, or short to battery positive. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 23

Go to Step 19

15

Test horizontal motor position sensor low reference circuit for open or short to battery positive. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 23

Go to Step 19

16

Inspect for poor connections at the harness connector of the power seat switch assembly. 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 23

Go to Step 20

17

Inspect for poor connections at the harness connector of the horizontal motor control circuits. 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 23

Go to Step 21

18

Inspect for poor connections at the harness connector of the horizontal motor position sensor circuits. 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 23

Go to Step 21

19

Inspect for poor connections at the harness connector of the memory seat 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 23

Go to Step 22

20

Replace the power seat switch assembly. Refer to Power Seat Switch Replacement

Did you complete the replacement?

--

Go to Step 23

--

21

Replace the horizontal motor. Refer to Front Seat Adjuster Motor Replacement

Did you complete the replacement?

--

Go to Step 23

--

22

Replace the memory seat module. Refer to Memory Seat Control Module Replacement .

Did you complete the replacement?

--

Go to Step 23

--

23

Operate the system to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3