• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Seat Adjuster Switch B+ | 1 | 1 | -- | -- |
Front Vertical Motor Down Control | 1 | 1 | -- | -- |
Front Vertical Motor Up Control | 1 | 1 | -- | -- |
Horizontal Motor Forward Control | 1 | 1 | -- | -- |
Horizontal Motor Rearward Control | 1 | 1 | -- | -- |
Rear Vertical Motor Down Control | 1 | 1 | -- | -- |
Rear Vertical Motor Up Control | 1 | 1 | -- | -- |
Recline Motor Forward Control | 1 | 1 | -- | -- |
Recline Motor Rearward Control | 1 | 1 | -- | -- |
Seat Adjuster Switch Ground | -- | 1 | -- | -- |
1. Power seat inoperative |
Power seat without memory is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch from the 30A SEATS circuit breaker that is located in the rear fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit and G302.
All seat motors are reversible. For example, when the seat horizontal forward switch is pressed to move the entire seat forward, battery voltage is applied through the switch contacts and the seat horizontal motor forward control circuit to the motor. The motor is grounded through the horizontal motor rearward switch contacts and the horizontal motor rearward control circuit to the motor. The motor runs in order to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.
Power Seats System Description and Operation
Control Module References for scan tool information
Operate the switches for the seat directional motors listed below in both directions. The seat should move in the commanded directions.
• | Seat front vertical motor |
• | Seat rear vertical motor |
• | Seat horizontal motor |
• | Seat recline motor |
⇒ | If the power seat is inoperative in all directions, refer to the Seat Adjuster Switch Circuit Test. |
⇒ | If 1 or more of the seat adjuster motors operate, refer to the Seat Adjuster Motor Circuit Test. |
• | Driver seat adjuster switch terminal B |
• | Passenger seat adjuster switch terminal D |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
• | Driver seat adjuster switch terminal E |
• | Passenger seat adjuster switch terminal A |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If the test lamp remains OFF during either of the commands, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal, test or replace the seat adjuster switch. |
⇒ | If not the specified value, replace the seat adjuster switch. |
⇒ | If greater than the specified range, replace the seat adjuster switch. |
⇒ | If greater than the specified range, replace the seat adjuster switch. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+ MSM Terminal C X1 | 1 | 1 | -- | -- |
B+ MSM Terminal A1 X4 | 2 | 2 | -- | -- |
B+ Seat Adjuster Switch | 2 | 1 | -- | -- |
Front Vertical Up Switch Signal | 2 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Front Vertical Down 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 | -- |
Driver Seat Front Vertical Motor Down Control | 1 | 1 | -- | -- |
Driver Seat Front Vertical Motor Up Control | 1 | 1 | -- | -- |
Driver Seat Horizontal Motor Forward Control | 1 | 1 | -- | -- |
Driver Seat Horizontal Motor Rearward Control | 1 | 1 | -- | -- |
Driver Seat Rear Vertical Motor Down Control | 1 | 1 | -- | -- |
Driver Seat Rear Vertical Motor Up Control | 1 | 1 | -- | -- |
Driver Seat Recline Motor Forward Control | 1 | 1 | -- | -- |
Driver Seat Recline Motor Rearward Control | 1 | 1 | -- | -- |
Ground - Seat Adjuster Switch | -- | 3 | -- | -- |
Ground - MSM | -- | 2 | -- | -- |
1. Power seat inoperative 2. Scan Tool Does Not Communicate with Low Speed GMLAN Device 3. No effect |
Battery voltage is supplied at all times to the memory seat module (MSM) from the 10A LGM/DSM fuse located in the rear fuse block. This voltage is used by the MSM for logic power and to supply battery voltage to the seat and lumbar adjuster switches. Battery voltage is supplied at all times to the MSM from the SEATS 30A circuit breaker located in the rear fuse block. This voltage is used by the MSM to drive the driver seat adjuster motors, recline motor and the lumbar motor.
All motors are reversible. For example, when the seat switch is pressed to move the seat forward, battery voltage is applied through the switch contacts and the seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery voltage through the seat horizontal motor forward control circuit and ground through the seat horizontal motor rearward control circuit to the motor. The motor runs to drive the seat forward until the switch is released. Moving the seat rearward works similarly to moving the seat forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction.
Memory Seats Description and Operation
Control Module References for scan tool information
⇒ | If any of the switch input parameters are Inactive or Invalid while the switch is pressed, refer to the Seat Adjuster Switch Circuit Test |
⇒ | 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. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If the test lamp remains OFF during either of the commands, test the control circuits for a short to ground or an open/high resistance. If the circuits test 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 |
⇒ | 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. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for MSM replacement, programming, and setup. |