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Home >> Mercury >> 2011 >> Grand Marquis V8-4.6L >> Repair and Diagnosis >> Body and Frame >> Seats >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test M: The Heated Seat Is Inoperative - Driver, Does Not Operate in High

Pinpoint Test M: The Heated Seat Is Inoperative - Driver, Does Not Operate in High




Seats

Pinpoint Tests

Pinpoint Test M: The Heated Seat is Inoperative - Driver, Does Not Operate in High

Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number

Normal Operation

The heated seat module is supplied battery and switched ignition voltage. The heated seat is activated when the heated seat switch supplies a ground signal to one of 2 input circuits into the heated seat module. One circuit activates the system to hi or off. The other circuit activates the system to low or off. Once activated, the heated seat module supplies voltage and ground to the heater mat to heat the seat cushion and backrest. The heated seat module monitors the temperature sensor in the cushion heater mat to maintain the seat temperature. The system will remain on until the module times-out or is switched off.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat switch
- Heated seat module

PINPOINT TEST M: THE HEATED SEAT IS INOPERATIVE - DRIVER, DOES NOT OPERATE IN HIGH

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

NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.

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M1 CHECK THE HEATED SEAT SWITCH AND CIRCUIT RESISTANCE


- Ignition OFF.
- Depower the Supplemental Restraint System (SRS). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Driver Seat Side Air Bag C315.
- Connect: Restraint System Diagnostic Service Tool to Driver Seat Side Air Bag C315.
- Disconnect: Driver Heated Seat Module C359.
- Measure resistance between driver heated seat module C359-8, circuit 1020 (DG/VT), harness side and ground while pressing the heated seat switch.




- Is the resistance less than 50 ohms with the heated seat switch pressed and greater than 10,000 ohms with the heated seat switch at rest?

Yes
INSTALL a new heated seat module. REFER to Heated Seat Module Heated Seat Module. 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. CONNECT driver seat side air bag module C315. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

No
GO to M2.

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M2 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR AN OPEN OR SHORT TO GROUND


- Disconnect: Driver Heated Seat Switch C538.
- Measure resistance between:
- driver heated seat switch C538-6, circuit 1020 (DG/VT), harness side and driver heated seat module C359-8, circuit 1020 (DG/VT), harness side.
- driver heated seat switch C538-6, circuit 1020 (DG/VT), harness side and ground.




- Is the resistance less than 5 ohms between the heated seat switch and heated seat module and greater than 10,000 ohms between the heated seat switch and ground?

Yes
GO to M3.

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. CONNECT driver seat side air bag module C315. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

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M3 CHECK THE HEATED SEAT SWITCH CIRCUIT FOR A SHORT TO VOLTAGE


- Ignition OFF.

- 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. Refer to Battery, Mounting and Cables Battery Disconnect.
- Ignition ON.
- Measure voltage between the driver heated seat module C359-8, circuit 1020 (DG/VT), harness side and ground.




- Is any voltage present?

Yes
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. CONNECT driver seat side air bag module C315. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

No
INSTALL a new heated seat switch. REFER to Heated Seat Switch Heated Seat 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. CONNECT driver seat side air bag module C315. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.

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