• | 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 | 3 | 3 | -- | -- |
Front Vertical Motor Up Control | 3 | 3 | -- | -- |
Horizontal Motor Forward Control | 2 | 2 | -- | -- |
Horizontal Motor Rearward Control | 2 | 2 | -- | -- |
Rear Vertical Motor Down Control | 4 | 4 | -- | -- |
Rear Vertical Motor Up Control | 4 | 4 | -- | -- |
Seat Adjuster Switch Ground | -- | 1 | -- | -- |
1. Power seat inoperative 2. Seat horizontal motor is inoperative 3. Seat front vertical motor is inoperative 4. Seat rear vertical motor is inoperative |
Battery voltage is supplied at all times to the driver and passenger seat adjuster switches through the PWR SEATS MSM 30 A circuit breaker located in the I/P fuse block. When a seat adjuster switch is in an inactive state, the switch contacts are closed to the switch ground circuit.
All power seat adjuster 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 operate this way.
Power Seats System Description and Operation
Operate the seat adjuster switches for the seat directional motors listed below in both directions. The seat should move in the commanded directions.
• | Seat horizontal motor |
• | Seat front vertical motor |
• | Seat rear vertical motor |
⇒ | If all power seat functions are inoperative, refer to the Seat Adjuster Switch Circuit Test. |
⇒ | If one or more of the seat adjuster motors operate, refer to the Seat Adjuster Motor Circuit Test. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
• | Seat horizontal motor terminal A and terminal B |
• | Seat front vertical motor terminal C and terminal D |
• | Seat rear vertical motor terminal E and terminal F |
⇒ | If the test lamp remains OFF for 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. |
• | Front vertical upward switch terminal B |
• | Front vertical downward switch terminal D |
• | Rear vertical upward switch terminal A |
• | Rear vertical downward switch terminal G |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
⇒ | If not the specified value, replace the seat adjuster switch. |
• | Front vertical upward switch terminal B |
• | Front vertical downward switch terminal D |
• | Rear vertical upward switch terminal A |
• | Rear vertical downward switch terminal G |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
⇒ | If greater than the specified range, replace the seat adjuster switch. |
• | Front vertical upward switch terminal B |
• | Front vertical downward switch terminal D |
• | Rear vertical upward switch terminal A |
• | Rear vertical downward switch terminal G |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
⇒ | 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 |
---|---|---|---|---|
Memory Seat Module B+ Terminal B11 X2 | B1420 | B1420 | -- | -- |
Memory Seat Module B+ Terminal A X1 | 2 | 2 | -- | -- |
Seat Adjuster Switch B+ | B1420 | 1 | -- | -- |
Power Seat Front Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Front Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Horizontal Rearward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Horizontal Forward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Rear Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Rear Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Driver Seat Front Vertical Motor Down Control | B1336 | 1 | -- | -- |
Driver Seat Front Vertical Motor Up Control | B1336 | 1 | -- | -- |
Driver Seat Rear Vertical Motor Down Control | B1336 | 1 | -- | -- |
Driver Seat Rear Vertical Motor Up Control | B1336 | 1 | -- | -- |
Driver Seat Horizontal Motor Forward Control | B1336 | 1 | -- | -- |
Driver Seat Horizontal Motor Rearward Control | B1336 | 1 | -- | -- |
Memory Seat Module Ground | -- | 2 | -- | -- |
|
Battery positive voltage is supplied at all times to the seat adjuster switch, memory seat adjuster switch, and memory seat module (MSM) from the TILT/TELE SW/MEM SEAT MOD 10A fuse located in the Body Control Module (BCM) fuse block. When a seat adjustment switch is pressed, battery voltage is applied through the switch contacts and the appropriate switch signal circuit to the MSM. The MSM then commands the selected seat motor to move in response to the switch signal.
All motors are reversible. For example, when the seat switch is operated to moved the entire seat forward, battery positive voltage is applied through the horizontal forward switch contacts and the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery positive voltage through the driver seat horizontal motor forward control circuit to the horizontal motor. The MSM supplies ground to the motor through the driver seat horizontal motor rearward control circuit. The motor runs 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 the opposite circuits causing the motor to run in the opposite direction. All other seat motors are also powered this way.
The memory seat module is also referred to as the Driver Position Module in certain scan tool menus.
Power Seats System Description and Operation
Control Module References for scan tool information
⇒ | If the reading does not change between the specified values, 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. |
⇒ | 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 B |
• | Front vertical down switch terminal D |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
• | Rear vertical up switch terminal A |
• | Rear vertical down switch terminal G |
• | Front vertical up switch terminal B |
• | Front vertical down switch terminal D |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
• | Rear vertical up switch terminal A |
• | Rear vertical down switch terminal G |
⇒ | If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. |
• | Seat horizontal motor terminal A and terminal B |
• | Seat front vertical motor terminal C and terminal D |
• | Seat rear vertical motor terminal E and terminal F |
⇒ | 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 B |
• | Front vertical down switch terminal D |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
• | Rear vertical up switch terminal A |
• | Rear vertical down switch terminal G |
⇒ | If not the specified value, replace the seat adjuster switch. |
• | Front vertical up switch terminal B |
• | Front vertical down switch terminal D |
• | Horizontal forward switch terminal C |
• | Horizontal rearward switch terminal F |
• | Rear vertical up switch terminal A |
• | Rear vertical down switch terminal G |
⇒ | 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, setup, and programming |