Pinpoint Test M: The Power Lumbar Is Inoperative - Passenger
Seats
Pinpoint Test M: The Power Lumbar is Inoperative - Passenger
Refer to Wiring Diagram Set 120, Power Seats for schematic and connector information Electrical Diagrams.
Normal Operation
The seat control switch contains the lumbar button and when pressed, supplies battery voltage and ground to the power lumbar motor to move the lumbar assembly in the desired direction.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Seat control switch
- Power lumbar motor assembly
PINPOINT TEST M : THE POWER LUMBAR IS INOPERATIVE - PASSENGER
NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Restraints and Safety Systems &/or Air Bag Systems.
NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS (Supplemental Restraint System) fault.
NOTE: The SRS (Supplemental Restraint System) must be fully operational and free of faults before releasing the vehicle to the customer.
M1 CHECK FOR VOLTAGE TO THE SEAT CONTROL SWITCH
- Ignition OFF.
- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C327.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
Connect the battery ground cable.
- Disconnect: Passenger Seat Control Switch C3026.
- Measure the voltage between passenger seat control switch C3026-5, circuit SBB42 (YE/RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to M2.
No
VERIFY Battery Junction Box (BJB) fuse 42 (30A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagrams to identify possible causes of the circuit short Electrical Diagrams. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
M2 CHECK THE SEAT CONTROL SWITCH GROUND FOR AN OPEN
- Measure the resistance between passenger seat control switch C3026-3, circuit GD145 (BK/BU), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to M3.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
M3 CHECK THE POWER LUMBAR MOTOR
- Connect: Passenger Seat Control Switch C3026.
- Disconnect: Power Lumbar Motor C3216.
- NOTE: During the following step, the voltage being measured changes polarity dependent upon which direction the seat control switch is activated.
While operating the seat control switch in both directions, measure the voltage between power lumbar motor C3216-1, circuit CPS88 (GY/OG), harness side and power lumbar motor C3216-2, circuit CPS89 (BU/BN), harness side.
Is the voltage greater than 10 volts when the seat control switch is operated and 0 volt in the rest position?
Yes
INSTALL a new power lumbar assembly. REFER to Lumbar Assembly - Power . TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to M4.
M4 CHECK THE LUMBAR MOTOR CIRCUITS FOR A SHORT TO GROUND
- Disconnect: Passenger Seat Control Switch C3026.
- Measure the resistance between:
- passenger seat control switch C3026-10, circuit CPS88 (GY/OG), harness side and ground.
- passenger seat control switch C3026-7, circuit CPS89 (BU/BN), harness side and ground.
Are the resistances greater than 10,000 ohms.
Yes
GO to M5.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
M5 CHECK THE POWER LUMBAR MOTOR CIRCUITS FOR AN OPEN
- Measure the resistance between:
- passenger seat control switch C3026-10, circuit CPS88 (GY/OG), harness side and power lumbar motor C3216-1, circuit CPS88 (GY/OG), harness side.
- passenger seat control switch C3026-7, circuit CPS89 (BU/BN), harness side and power lumbar motor C3216-2, circuit CPS89 (BU/BN), harness side.
Are the resistances less than 5 ohms?
Yes
INSTALL a new seat control switch. REFER to Seat Control Switch - Front . TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.