COMPRESSOR CONTROLS
K2
CIRCUIT OPERATION
1
CIRCUIT OPERATION
Compressor Control (MFI–V8)
With the Ignition Switch (X134) in position II, battery
voltage is applied to the Ignition Load Relay (K127).
The relay is energised, applying battery voltage to
the Compressor Clutch Relay (K108) and the A/C
Logic Relay (K170). When the Front Fan Speed
Switch (X247) is turned to positions I, II, III, or IV
and the Front A/C Switch (X225) is turned on,
ground is provided to terminal 86 of the A/C Logic
Relay (K170) through the closed contacts of the A/C
Dual Pressure Switch (X102) and the Front A/C
Evaporator Temperature Switch (X101).
The relay is energised, applying battery voltage to
the Engine Control Module (ECM) (Z132), which
signals the ECM that compressor operation has
been requested. The ECM then provides ground to
the coil of the Compressor Clutch Relay (K108). The
relay is energised, applying battery voltage to the
Compressor Clutch (K107). Compressor Clutch
operation is now controlled by the status of the A/C
Dual Pressure Switch (X102) and the Front A/C
Evaporator Temperature Switch (X101).
The Front A/C Evaporator Temperature Switch
(X101) is fitted in the airflow out of the front
evaporator to sense the temperaure of the exterior
fins. Should ice begin to form due to low
temperature, the switch will open. The A/C Dual
Pressure Switch (X102) monitors refrigerant
pressure in the high pressure line. Should pressure
become too high or too low, the switch will open.
When one or both of these switches open, the
ground supply to terminal 86 of the A/C Logic Relay
(K170) will be interrupted. The relay de–energises,
removing battery voltage from the Engine Control
Module (ECM) (Z132), which signals the ECM that
compressor operation should be turned off. The
ECM removes the ground supply to the coil of the
Compressor Clutch Relay (K108). The relay then
de–energises, removing battery voltage from the
Compressor Clutch (K107), thereby disengaging the
Compressor.
Compressor Control (MFI–T16)
With the Ignition Switch (X134) in position II, battery
voltage is applied to the Compressor Clutch Relay
(K108) and the A/C Logic Relay (K170). When the
Front Fan Speed Switch (X247) is turned to
positions I, II, III, or IV and the Front A/C Switch
(X225) is turned on, ground is provided to terminal
85 of the A/C Logic Relay (K170) through the closed
contacts of the A/C Dual Pressure Switch (X102)
and the Front A/C Evaporator Temperature Switch
(X101).
The relay is energised, applying ground to terminal
35 of the Engine Control Module (ECM) (Z132),
which signals the ECM that compressor operation
has been requested. The ECM then provides ground
to the terminal 86 of the Compressor Clutch Relay
(K108). The relay is energised, applying battery
voltage to the Compressor Clutch (K107).
Compressor Clutch operation is now controlled by
the status of the A/C Dual Pressure Switch (X102)
and the Front A/C Evaporator Temperature Switch
(X101).
The Front A/C Evaporator Temperature Switch
(X101) is fitted in the airflow out of the front
evaporator to sense the temperaure of the exterior
fins. Should ice begin to form due to low
temperature, the switch will open. The A/C Dual
Pressure Switch (X102) monitors refrigerant
pressure in the high pressure line. Should pressure
become too high or too low, the switch will open.
When one or both of these switches open, the
ground supply to terminal 85 of the A/C Logic Relay
(K170) will be interrupted. The relay de–energises,
removing the ground supply from terminal 35 of the
Engine Control Module (ECM) (Z132), which signals
the ECM that compressor operation should be
turned off. The ECM removes the ground supply to
terminal 86 of the Compressor Clutch Relay (K108).
The relay then de–energises, removing battery
voltage from the Compressor Clutch (K107), thereby
disengaging the Compressor.
Compressor Control (NAS) (SFI–V8)
With the Ignition Switch (X134) in position II, battery
voltage is applied to the Ignition Load Relay (K127).
The relay is energised, applying battery voltage to
the Compressor Clutch Relay (K108). When the
Front Fan Speed Switch (X247) is turned to
positions I, II, III, or IV and the Front A/C Switch
(X225) is turned on, ground is provided to terminal
28 of the Engine Control Module (ECM) (Z132)
through the closed contacts of the A/C Dual
Pressure Switch (X102) and the Front A/C
Evaporator Temperature Switch (X101). The signal
informs the ECM that compressor operation has
been requested. The ECM then provides ground to
the coil of the Compressor Clutch Relay (K108). The
relay is energised, applying battery voltage to the
Compressor Clutch (K107). Compressor Clutch
operation is now controlled by the status of the A/C
Dual Pressure Switch (X102) and the Front A/C
Evaporator Temperature Switch (X101).