Pinpoint Tests: Notes

WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Both Heated Rear Seats are Inoperative

Refer to Climate Controlled Seats for schematic and connector information.

Normal Operation and Fault Conditions

When the LH or RH heated rear seat control switch is activated with the ignition ON, a momentary ground signal is supplied to the heated seat module to operate the system. The system cycles through high heat mode, low heat mode or OFF, each time the switch is pressed. The heated seat module supplies voltage to the LH or RH rear seat cushion and backrest heater mats, which are connected in series. Seat temperature is maintained by the heated seat module using a sensor contained within each cushion heater mat. The heated seat module supplies a reference voltage to the temperature sensor and monitors the return signal from the temperature sensor for controlling current flow to the heater mats. The heated seat module remains ON, heating the seat and maintaining temperature until switched OFF or the ignition voltage is switched OFF.

Possible Sources

Fuse(s)
Wiring, terminals or connectors
Heated seat module
BCM

Visual Inspection and Diagnostic Pre-checks

Verify BCM fuse 36 (15A) is OK.
Verify BJB fuse 83 (20A) is OK.