The electronic climate control (ECC) module serves as an
interface between the passenger and the air delivery system. The ECC module
compares passenger selections with environmental conditions and will adjust
air delivery accordingly.
The following air delivery modes are available:
| • | External air circulation |
| • | Internal air circulation |
The ECC module requires two voltage sources in order to operate. Voltage
is available at all times through the RDO BATT fuse 19 and CKT 340
(ORN).
When the ignition switch is in the RUN position, voltage is available
through the HVAC I fuse 21 and CKT 341 (BRN).
A path to ground for the ECC module is provided by CKT 1050 (BLK)
to grounds G203/G204.
The ECC module receives inputs from the following temperature sensors:
| • | The inside air temperature sensor and CKT 734 (DK GRN) |
| | A fan located internally to the inside air temperature sensor housing
continually draws passenger compartment air over the sensor increasing accuracy
of the temperature reading. The HVAC I fuse applies voltage to CKT 341
(BRN) for the fan motor when the ignition switch is in the RUN position.
A path to ground for the fan motor is provided by CKT 1850 (BLK)
to ground G202. |
| • | The outside air temperature sensor and CKT 636 (DK GRN/WHT) |
| • | The sun load temperature sensor and CKT 590 (LT BLU/BLK) |
| • | The upper discharge air temperature sensor and CKT 404
(BRN) |
| • | The lower discharge air temperature sensor and CKT 405
(LT GRN) |
CKT 552 (BLK) provides the common ground path for the sensors
back to the ECC module.
The ECC module will use the sensor information in order to determine
how much airflow to the heater core is required and will adjust the air temperature
valve accordingly. The air temperature valve is located internally to the
heater core housing. The position of the air temperature valve is reported
to the ECC module by the air temperature valve sensor and motor. The HVAC
I fuse applies voltage to CKT 341 (BRN) for the air temperature valve
sensor and motor when the ignition switch is in the RUN position.
Operation of the air temperature valve sensor and motor is supported
by the following circuits:
| • | CKT 1688 (LT BLU/BLK) for the 5 volt
reference |
| • | CKT 1791 (YEL) for the ground reference |
| • | CKT 733 (LT BLU) for the signal return path |
| • | CKT 1199 (DK BLU) for the motor drive signal |
The ECC module will control the actuation of individual solenoids of
the HVAC solenoid assembly in order to direct air to the appropriate outlets.
The HVAC I fuse applies voltage to CKT 341 (BRN) for the HVAC solenoid
assembly when the ignition switch is in the RUN position. With voltage available
the ECC module will complete the current path to ground.
The ECC module control of the HVAC solenoid assembly is supported by
the following circuits:
