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Home >> Ford >> 2012 >> Mustang Base, 2D Coupe, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 432 (Seat System - Seats) >> Diagnosis And Testing >> Seating >> Pinpoint Tests >> Pinpoint Test F: The Heated Seats are Inoperative >> Normal Operation

Normal Operation

WARNING: This page is about a different car, the 2013 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

With the ignition ON, voltage is supplied from the Smart Junction Box (SJB) to each heated seat relay coil on circuit CBP43 (GY). Battery voltage is also supplied to the heated seat relay contacts (hot at all times) on circuit SBB16 (VT/RD). When the heated seat buttons are pressed, the Front Controls Interface Module (FCIM) illuminates the heated seat indicators and transmits a system request message to the HVAC module on the communication network. The HVAC module provides ground to heated seat relay coil circuits CHS30 (GN/YE) (driver) and CHS29 (WH/BU) (passenger) to operate the system. The engine must be running and both modules must be communicating correctly for the system to operate.

The HVAC module monitors the heated seat relay coil circuits for open, short to ground and short to voltage. If circuit faults are detected and DTCs are set for both seats, the HVAC module removes ground from the relay coils to disable the system (refer to HVAC Module DTC Chart ). The HVAC module also transmits network communication messages to the FCIM to deactivate the heated seat indicators. PIDs are available in the FCIM using a scan tool to check the heated seat switches and confirm correct module communication.

The heated seat system does not time-out and remains on until switched off or the engine is off.

This pinpoint test is intended to diagnose the following: 

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