Mark VII V8-302 5.0L VIN F FI (1987)
Control Module HVAC: Description and Operation
Electronic Climate Control Module
A/C BLOWER MOTOR SPEED CONTROL
The electronic automatic temperature control assembly consists of nine push buttons for customer input, a vacuum fluorescent display (VFD) and
seven light emitting diodes (LEDs) to display the set temperature and mode selection. An integral rear window defrost control switch may also be used.
The VFD is also used to display diagnostic codes. The set temperature can be lowered or raised in increments of one degree between 65 and 85
degrees F through the use of a warmer or cooler button. There is also a 90 setting for max heat and a 60 setting for max cool.
Temperature settings will be displayed in degrees F/degrees C whenever the miles/km button on the message center is depressed. On models equipped
with a performance cluster, degrees F is permanently displayed.
The control assembly performs six functions. It processes data from the customer's input to the control panel, from in-vehicle, ambient and engine
temperature sensors, and from four actuator position sensors. When turned on, it remembers the last temperature and mode selected before the last
shutoff. It provides continuous position control of the blend and mode actuators. It provides discrete two position control of the PAN/DEF and OA/REC
actuators. It provides a continuously variable blower signal that is amplified by the solid state Blower Speed Control (BSC) module to control blower
voltage. It provides an A/C clutch On-Off signal which is amplified and delivered to the pressure switch by the BSC module.
