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 out limit switch signal circuit is considered to be active when the circuit reference voltage is low or closed to ground by the switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 025 Swivel Out Limit Switch Does Not Become Active After 13 Seconds of Outward Rotation

Conditions for Running the DTC

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

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

The module will stop outward rotation and only allow additional outward 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: Power Seats Schematics

1

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

Go to Step 2

Go to Symptoms - Seats

2

Verify the fault is present.

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 rotate out to the swivel out hard stop?

Go to Step 4

Go to Step 5

4

  1. While the seat is in the outward facing position, disconnect the swivel out limit switch connector.
  2. Connect a jumper wire from the swivel out limit switch signal circuit terminal in the harness connector to ground.
  3. Attempt to operate the seat to the out of vehicle position.

Does the seat extend to the out of vehicle position?

Go to Step 6

Go to Step 7

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 out switch on the remote.

Does the test lamp illuminate?

Go to Step 10

Go to Step 8

6

Test the swivel out limit switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

7

Test the swivel out limit switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

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

Did you find and correct the condition?

Go to Step 11

Go to Step 9

9

Replace the mobility seat control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the repair complete?

Go to Step 11

--

10

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

Is the repair complete?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3