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Home >> Mercury >> 2009 >> Grand Marquis V8-4.6L >> Repair and Diagnosis >> Body and Frame >> Seats >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test A: The Power Seat Is Inoperative

Pinpoint Test A: The Power Seat Is Inoperative




Seats

Pinpoint Test A: The Power Seat is Inoperative

Refer to Wiring Diagram Set 120, Power Seats for schematic and connector information. Diagrams By Number

Normal Operation

The seat control switch is supplied battery voltage on circuit 517 (BK/WH) and is supplied ground on circuit 57 (BK). The seat control switch applies battery voltage and ground directly to one of 3 bi-directional seat track motors, respectively, to move the seat. Toggling the seat control switch in the opposite direction reverses voltage polarity applied to the respective seat motor and moves the seat in the opposite direction.

This pinpoint test is intended to diagnose the following:
- Circuit breaker
- Wiring, terminals or connectors
- Seat control switch
- Seat track (motor assembly)



PINPOINT TEST A: THE POWER SEAT IS INOPERATIVE

WARNING: Remove restraint system diagnostic tools from the vehicle prior to road testing. If tools are not removed, the supplemental restraint system (SRS) device may not deploy in a crash. Failure to follow this instruction may result in serious personal injury or death in a crash and possibly violate vehicle safety standards.

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTICE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test. Inspection and Verification

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A1 CHECK THE POWER SEAT OPERATION


- Operate the seat from the seat control switch.
- Does the seat move in any direction?

Yes
VERIFY the symptom. GO to Symptom Chart. Symptom Related Diagnostic Procedures

No
GO to A2.

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A2 CHECK THE VOLTAGE TO THE SEAT CONTROL SWITCH


- Ignition OFF.
- Depower the Supplemental Restraint System (SRS). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Driver Seat Side Air Bag C315 or Passenger Seat Side Air Bag C316.
- Connect: Restraint System Diagnostic Service Tool 418-133 to Driver Seat Side Air Bag C315 or Passenger Seat Side Air Bag C316.
- Disconnect: Driver Seat Control Switch C519 or Passenger Seat Control Switch C627.

- 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 voltage between driver seat control switch C519-10, circuit 517 (BK/WH), harness side and ground; or between passenger seat control switch C627-10, circuit 517 (BK/WH), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to A3.

No
VERIFY the Battery Junction Box (BJB) circuit breaker 601 (20A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.

DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic service tool from driver seat side air bag module C315 or passenger seat side air bag module C316. CONNECT driver seat side air bag module C315 or passenger seat side air bag module C316. REPOWER the SRS. REFER to Air Bag Systems.

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A3 CHECK CIRCUIT 57 (BK) FOR AN OPEN


- Measure resistance between driver seat control switch C519-6, circuit 57 (BK), harness side and ground; or between passenger seat control switch C627-6, circuit 57 (BK), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to A4.

No
REPAIR the circuit. TEST the system for normal operation.

DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic service tool from driver seat side air bag module C315 or passenger seat side air bag module C316. CONNECT driver seat side air bag module C315 or passenger seat side air bag module C316. REPOWER the SRS. REFER to Air Bag Systems.

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A4 CHECK THE SEAT TRACK FOR AN OBSTRUCTION


- Inspect the seat track for damage or an obstruction.
- Is the seat track OK?

Yes
INSTALL a new seat control switch. REFER to Seat Control Switch Seat Control Switch. TEST the system for normal operation.

DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic service tool from driver seat side air bag module C315 or passenger seat side air bag module C316. CONNECT driver seat side air bag module C315 or passenger seat side air bag module C316. REPOWER the SRS. REFER to Air Bag Systems.

No
INSTALL a new seat track. REFER to Seat Track Seat Track. TEST the system for normal operation.

DISCONNECT the battery ground cable. DISCONNECT the restraint system diagnostic service tool from driver seat side air bag module C315 or passenger seat side air bag module C316. CONNECT driver seat side air bag module C315 or passenger seat side air bag module C316. REPOWER the SRS. REFER to Air Bag Systems.

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