The front heater and air Conditioning (A/C) functions are
controlled by the Heating, Ventilation and Air Conditioning (HVAC) control
module which include the following components:
| • | The temperature control motor |
The battery voltage is provided to the controls by the HTR-A/C
Fuse (Fuse 12). The high speed blower voltage is provided by the A/C
FUSE. When the blower relay is energized, the voltage is provided directly
to the blower motor. The blower relay is located in the blower motor resistor
and relay pack.
The blower speed is controlled by the fan switch in conjunction with
the mode switch. Voltage from CKT 141 (BRN) is passed through the mode
switch. The voltage is then passed on to the fan switch for all of the
mode settings except OFF. The A/C FUSE and CKT 542 (RED) provides
the battery voltage to the blower motor resistor and relay pack when the
fan switch is in the HIGH position. CKT 350 (BLK) cavity C
provides a ground for the following components:
| • | The coil of the blower high speed relay |
When the blower high speed relay is energized, the circuit to the front
blower motor is completed. The energized blower high speed replay bypasses
the resistor pack. The energized blower high speed relay will operate
the blower motor at high speed.
Increasing the resistance limits the current to the blower motor. Limiting
the current results in slower blower motor speeds.
A current path is provided through the following components when the
M2 setting is selected:
| • | Cavity F of the blower motor resistor and relay pack |
| • | The closed contract of the high speed blower relay |
The circuit puts 1 resistor in the circuit.
Place the fan switch in the M1 position in order to attain a lower speed.
The lower speed provides a current path through the switch to CKT 63
(TAN) cavity D of the blower motor resistor and relay pack. The current
places 2 resistors in the circuit. The 2 resistors reduce the current
flow to the front blower motor. The reduced current flow reduces the blower
motor speed.
Place the 3 resistors in the circuit in order to accomplish the slowest
blower speed. The 3 resistors are placed in the circuit when the LOW setting
is selected from the fan switch. The current flows through CKT 60
(YEL) cavity E of the blower motor resistor and relay pack through
the following components:
| • | The closed contacts of the high speed blower relay |
3 resistors are placed in the circuit. The 3 resistors reduce the current
flow to the front blower motor. The reduced current flow reduces the blower
motor speed.
