Pinpoint Test E: The Power Lumbar is Inoperative
Seats
Pinpoint Test E: The Power Lumbar is Inoperative
Refer to Wiring Diagram Set 120, Seating for schematic and connector information [1][2]Diagrams By Number.
Normal Operation
The lumbar control switch is supplied battery voltage on circuit SBB32 (VT/RD) and ground on circuit GD133 (BK). When the lumbar control switch is pressed, voltage and ground are supplied to the power lumbar motor on circuits CPS65 (WH/GN) and CPS64 (BN/VT) to move the lumbar assembly in or out.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Lumbar control switch
- Power lumbar assembly
PINPOINT TEST E : THE POWER LUMBAR IS INOPERATIVE
E1 CHECK THE LUMBAR CONTROL SWITCH FOR VOLTAGE
- 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: Driver Seat Side Air Bag C367.
- Disconnect: Lumbar Control Switch C361.
- 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.
- Measure the voltage between lumbar control switch C361-4, circuit SBB32 (VT/RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to E2.
No
VERIFY Battery Junction Box (BJB) fuse 32 (30A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
E2 CHECK THE GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between:
- lumbar control switch C361-2, circuit GD133 (BK), harness side and ground.
- lumbar control switch C361-8, circuit GD133 (BK), harness side and ground.
Are the resistances less than 5 ohms?
Yes
GO to E3.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
E3 CHECK FOR VOLTAGE TO THE LUMBAR MOTOR
- Connect: Lumbar Control Switch C361.
- Disconnect: Power Lumbar Motor C366.
- Measure the voltage between power lumbar motor C366-1, circuit CPS64 (BN/VT), harness side and power lumbar motor C366-2, circuit CPS65 (WH/GN), harness side.
- Operate the power lumbar control switch in both directions.
Is the voltage greater than 10 volts in both directions?
Yes
INSTALL a new power lumbar assembly. REFER to Lumbar Assembly . TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to E4.
E4 CHECK THE LUMBAR MOTOR CIRCUITS FOR A SHORT TO GROUND
- Disconnect: Lumbar Control Switch C361.
- Measure the resistance between:
- lumbar control switch C361-3, circuit CPS64 (BN/VT), harness side and ground.
- lumbar control switch C361-7, circuit CPS65 (WH/GN), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to E5.
No
REPAIR the circuit(s). TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
E5 CHECK THE LUMBAR MOTOR CIRCUITS FOR AN OPEN
- Measure the resistance between power lumbar switch C361, harness side and power lumbar motor C366, harness side, using the following chart:
Power Lumbar Switch Circuit Power Lumbar Motor C361-3 CPS64 (BN/VT) C366-1 C361-7 CPS65 (WH/GN) C366-2
Are the resistances less than 5 ohms?
Yes
INSTALL a new lumbar control switch. REFER to Lumbar Control Switch . TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
REPAIR the circuit(s). TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C367. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.