Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B1735: Driver Seat Front Up Switch Circuit MalfunctionDTC B1740: Driver Seat Front Down Switch Circuit Malfunction
DTC B1745: Driver Seat Rear Up Switch Circuit Malfunction
DTC B1750: Driver Seat Rear Down Switch Circuit Malfunction
DTC B1755: Driver Seat Assembly Forward Switch Circuit Malfunction
DTC B1760: Driver Seat Assembly Rearward Switch Circuit Malfunction
DTC B1815: Driver Seat Recline Forward Switch Circuit Malfunction
DTC B1820: Driver Seat Recline Rearward Switch Circuit Malfunction
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Seat Adjuster Switch B+ | 2 | 1 | -- | -- |
Front Vertical Down Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Front Vertical Up Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Horizontal Forward Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Horizontal Rearward Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Rear Vertical Down Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Rear Vertical Up Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Recline Forward Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Recline Rearward Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
1. Power seat inoperative 2. Scan Tool Does Not Communicate With Low Speed GMLAN Device | ||||
Circuit/System Description
The seat adjuster switches are inputs to the memory seat module (MSM). Battery voltage from the MSM is supplied at all times to the seat adjuster switch. When the seat switches are pressed, they send a 12 volt signal through the switch signal circuits to the MSM. The MSM then commands the driver seat motors to move in response to the switch signals.
Conditions for Running the DTC
The MSM must be powered.
Conditions for Setting the DTC
| • | If a seat switch circuit is active in one direction and the switch for the opposite direction is pressed, this DTC will set. |
| • | A short to voltage on a switch signal circuit. |
Action Taken When the DTC Sets
| • | A motor output driven in response to a switch considered failed, is deactivated for both directions. |
| • | All memory recall commands are ignored. |
| • | The MSM will respond to any other switch signal that has not set a DTC. |
The seat module will disable the seat adjuster function for which the DTC has set.
Conditions for Clearing the DTC
| • | The current DTC will clear and set the code to history, 3 seconds after the fault is no longer present and the power mode changes to OFF then back to ACC or RUN. |
| • | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred. |
Diagnostic Aids
| • | The scan tool may reference the Memory Seat Module as the Driver Seat Module. |
| • | If one of the switch signal circuits is shorted to battery, multiple codes will set. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Driver Seat Module seat switch parameters while pressing the appropriate seat directional switches. The reading should change between Inactive and Up/Down or Froward/Back.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground.
- Verify the scan tool seat switch parameters listed below are Inactive:
- Install a 3A fused jumper wire between the appropriate signal circuit listed below and the B+ circuit terminal E. Verify the appropriate scan tool seat position switch parameter is Forward/Rearward or Up/Down.
- If all circuits test normal, test or replace the seat adjuster switch.
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
| • | Recline Switch |
| • | Horizontal Position Switch |
| • | Rear Vertical Position Switch |
| • | Front Vertical Position Switch |
| ⇒ | If not the specified value, test the appropriate signal circuit listed below for a short to voltage. If the circuit tests normal, replace the MSM. |
| • | Front vertical up switch terminal K |
| • | Front vertical down switch terminal J |
| • | Rear vertical up switch terminal H |
| • | Rear vertical down switch terminal G |
| • | Horizontal forward switch terminal D |
| • | Horizontal rearward switch terminal C |
| • | Recline forward switch terminal F |
| • | Recline rearward switch terminal A |
| • | Front vertical up switch terminal K |
| • | Front vertical down switch terminal J |
| • | Rear vertical up switch terminal H |
| • | Rear vertical down switch terminal G |
| • | Horizontal forward switch terminal D |
| • | Horizontal rearward switch terminal C |
| • | Recline forward switch terminal F |
| • | Recline rearward switch terminal A |
| ⇒ | If not the specified value, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. |
Component Testing
Seat Adjuster Switch Test
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- Test for infinite resistance between each signal terminal listed below and the B+ terminal E with the switch in the open position.
- Test for less than 1 Ω between each signal terminal listed below and the B+ terminal E with the switch in the closed position.
| • | Front vertical up switch terminal K |
| • | Front vertical down switch terminal J |
| • | Rear vertical up switch terminal H |
| • | Rear vertical down switch terminal G |
| • | Horizontal forward switch terminal D |
| • | Horizontal rearward switch terminal C |
| • | Recline forward switch terminal F |
| • | Recline rearward switch terminal A |
| ⇒ | If not the specified value, replace the seat adjuster switch. |
| • | Front vertical up switch terminal K |
| • | Front vertical down switch terminal J |
| • | Rear vertical up switch terminal H |
| • | Rear vertical down switch terminal G |
| • | Horizontal forward switch terminal D |
| • | Horizontal rearward switch terminal C |
| • | Recline forward switch terminal F |
| • | Recline rearward switch terminal A |
| ⇒ | If greater than the specified range, replace the seat adjuster switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, programming, and setup |
