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 lift upper 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 053 Lift Upper Limit Switch Does Not Become Active After 80 Seconds of Ascend
Conditions for Running the DTC
| • | Battery voltage must be within 9-16 volts. |
| • | Seat operation is attempted from the out of vehicle position. |
Conditions for Setting the DTC
While attempting to ascend the seat from the out of vehicle position the time from the lift lower limit switch becoming inactive to the lift upper switch becoming active exceeds 80 seconds.
Action Taken When the DTC Sets
The module will stop ascent operation and only allow additional ascent 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 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 ascend to the in vehicle hard stop? | Go to Step 4 | Go to Step 5 |
4 |
Does the signal circuit voltage change from high to low as the switch is opened and closed? | Go to Step 8 | Go to Step 6 |
5 |
Does the test lamp illuminate? | Go to Step 9 | Go to Step 7 |
6 | Test the lift upper limit switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
7 | Test the extender 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 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 | -- |
9 | Replace the mobility seat base unit. Refer to Sit-N-Lift Seat Base Replacement . Is the repair complete? | Go to Step 10 | -- |
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
