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 lower 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 043 Lift Lower Limit Switch Does Not Become Active After 35 Seconds of Descend
Conditions for Running the DTC
| • | Battery voltage must be within 9-16 volts. |
| • | Seat operation is attempted from the outward facing in vehicle position. |
Conditions for Setting the DTC
While attempting to descend the seat from the outward facing in vehicle position, the time from the lift upper limit switch becoming inactive to the lift lower switch becoming active exceeds 35 seconds.
Action Taken When the DTC Sets
The module will stop descent operation and only allow additional descent 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 descend out to the lower 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 6 | Go to Step 7 |
5 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 8 |
6 | Test the lift lower 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 lift lower 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 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 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 |
