GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The mobility seat module uses inputs from 4 limit switches in order to determine the seat position. The limit switch signal circuits are referenced from battery voltage within the module. The limit switches will open or close the switch signal circuits to ground in order for the module to determine them to be active or inactive. The swivel in limit switch signal circuit is considered to be active when the circuit reference voltage is high or open to ground by the switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 035 Swivel In Limit Switch Does Not Become Active After 13 Seconds of Inward Rotation

Conditions for Running the DTC

    • Battery voltage must be within 9-16 volts.
    • Seat operation is attempted from the outward facing position.

Conditions for Setting the DTC

While attempting to rotate the seat inward from the outward facing position the time from the swivel out limit switch becoming inactive to the swivel in switch becoming active exceeds 13 seconds.

Action Taken When the DTC Sets

The module will stop inward rotation and only allow additional inward rotation in 3-second intervals.

Conditions for Clearing the DTC

The DTC may be cleared by removing the main power supply or ground from the seat module.

Diagnostic Aids

Inspect the limit switch for any physical damage or obstructions to its mechanical operation which may cause the condition.

Step

Action

Yes

No

Schematic Reference: Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

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

Go to Step 2

Go to Power Seats System Description and Operation

2

Verify the fault is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Does the seat rotate in to the swivel in hard stop?

Go to Step 4

Go to Step 5

4

  1. Clear the DTC by removing the 25-amp circuit breaker for several seconds.
  2. While the seat is in the inward facing position disconnect the swivel out limit switch connector.
  3. Attempt to operate the seat to the outward facing position

Does the seat rotate to the outward facing position?

Go to Step 9

Go to Step 6

5

  1. Disconnect the swivel motor pigtail connector.
  2. Connect a test lamp between the motor control circuit terminals in the harness connector.
  3. Press the in switch on the remote.

Does the test lamp illuminate?

Go to Step 9

Go to Step 7

6

Test the swivel in limit switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Test the swivel motor control circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8

Replace the mobility seat control module. Refer to Sit-N-Lift Control Module Replacement .

Is the repair complete?

Go to Step 10

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9

Replace the mobility seat base unit. Refer to Sit-N-Lift Seat Base Replacement .

Is the repair complete?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3