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. |
Diagnostic Fault Information
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 | ||||
Circuit/System Description
Power seat without memory is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch through the CB2 25 A circuit breaker located in the I/P fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit.
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.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Power Seats System Description and Operation
Electrical Information Reference
Circuit/System Verification
Operate the seat switches for the seat directional motors listed below in both directions. The seat should move in the commanded directions.
| • | M51 Horizontal Motor |
| • | M50 Front Vertical Motor |
| • | M55 Rear Vertical Motor |
| • | M56 Recline Motor |
| ⇒ | If the power seat is inoperative in all directions, refer to the S64 Seat Adjuster Switch Circuit Test. |
| ⇒ | If 1 or more of the seat adjuster motors operate, refer to the Seat Adjuster Motor Circuit Test. |
Circuit/System Testing
S64 Seat Adjuster Switch Circuit Test
- Disconnect the harness connector at the S64 seat adjuster switch.
- Test for less than 5 Ω between the ground circuit terminal B and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal E and ground.
- If all circuits test normal, test or replace the S64 seat adjuster switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
Seat Adjuster Motor Circuit Test
- Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
- Connect a test lamp between control circuit terminal 1 and control circuit terminal 5.
- Ignition ON, command the appropriate seat motor Up and Down or Forward and Rearward using the seat adjuster switch. The test lamp should turn ON when commanding the up and down or forward and rearward states.
- If all circuits test normal, test or replace the seat motor.
| • | M51 horizontal motor |
| • | M50 front vertical motor |
| • | M55 rear vertical motor |
| • | M56 recline motor |
| ⇒ | 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 S64 seat adjuster switch. |
Component Testing
Seat Adjuster Switch
- Ignition OFF, disconnect the harness connector at the S64 seat adjuster switch.
- Test for infinite resistance between the B+ terminal E and each control terminal with the switch in the open position.
- Test for less than 1 Ω between the B+ terminal E and each control terminal with the appropriate switch in the closed position.
- Test for less than 1 Ω between the ground terminal B and each control terminal with the switch in the open position.
| ⇒ | If not the specified value, replace the S64 seat adjuster switch. |
| ⇒ | If greater than the specified range, replace the S64 seat adjuster switch. |
| ⇒ | If greater than the specified range, replace the S64 seat adjuster switch. |
Seat Motor
- Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
- Install a 30 A fused jumper wire between control terminal 1 and 12 V. Momentarily install a jumper wire between control terminal 5 and ground. The seat motor should momentarily perform the appropriate FORWARD/REARWARD/UP/DOWN function.
- Reverse the polarity of jumper wires. The a seat motor should perform in the opposite direction.
| • | M51 horizontal motor |
| • | M50 front vertical motor |
| • | M55 rear vertical motor |
| • | M56 recline motor |
Note: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.
| ⇒ | If the function does not perform as specified, replace the seat motor. |
| ⇒ | If the function does not perform as specified, replace the seat motor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
