When the excessive circuit load occurs often enough, the module shuts down the output until a repair procedure is carried out. The Field-Effect Transistor (FET) protected circuit has 3 predefined levels of short circuit tolerance based on the harmful effect of each circuit fault on the Field-Effect Transistor (FET) and the ability of the Field- Effect Transistor (FET) to withstand it. A module lifetime level of fault events is established based upon the durability of the Field-Effect Transistor (FET). If the total tolerance level is determined to be 600 fault events, the 3 predefined levels would be 200, 400 and 600 fault events.
When each tolerance level is reached, the short circuit DTC that was stored on the first failure cannot be cleared by a command to clear the Diagnostic Trouble Codes (DTCs). The module does not allow the DTC to be cleared or the circuit to be restored to normal operation until a successful self-test proves that the fault has been repaired. After the self-test has successfully completed (no on-demand Diagnostic Trouble Codes (DTCs) present), DTC U1000:00 and the associated DTC (the DTC related to the shorted circuit) automatically clears and the circuit function returns.
When each level is reached, the DTC associated with the short circuit sets along with DTC U1000:00. These Diagnostic Trouble Codes (DTCs) can be cleared using the diagnostic scan tool. The module never resets the fault event counter to zero and continues to advance the fault event counter as short circuit fault events occur.
If the number of short circuit fault events reach the third level, then Diagnostic Trouble Codes (DTCs) U1000:00 and U3000:49 set along with the associated short circuit DTC. DTC U3000:49 cannot be cleared and a new module must be installed after the repair.
The FCIM requires Programmable Module Installation (PMI) when it is replaced.
Ambient Air Temperature (AAT) Sensor
The Ambient Air Temperature (AAT) sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The Ambient Air Temperature (AAT) sensor is hardwired to the PCM through separate input and return circuits. If the outside air temperature is below approximately 0°C (32°F), the PCM does not allow the A/C compressor clutch to engage.
The PCM sends raw ambient air temperature data to the HVAC module. The HVAC module filters the raw data, sends it to the APIM and the touchscreen displays the outside temperature.
After replacing an Ambient Air Temperature (AAT) sensor, the sensor data must be reset by either driving the vehicle at speeds consistently about 20 MPH for at least 5 minutes to update the filtered data or perform the multiple button press reset procedure to update to the current raw value.
The multiple button reset for the Ambient Air Temperature (AAT) sensor is as follows:
On the HVAC panel controls, press the A/C and Recirc buttons simultaneously, then, release both. Within 2 seconds press the A/C button again.
Blower Motor
The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core housing and the plenum chamber where it is mixed and distributed.
Blower Motor Speed Control
The blower motor speed control uses a PWM signal from the FCIM to determine the desired blower speed and varies the ground feed for the blower motor to control the speed.
Compressor Clutch Assembly
When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate with the engine. When battery voltage
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.