DISCOVERY
ETM K2
to positions I, II, III, or IV and the Front A/C Switch
(X225) is turned On, ground is provided to terminal
CIRCUIT OPERATION
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).
Compressor Control (MFI–V8) (300Tdi with EDC)
With the Ignition Switch (X134) in position II,
battery voltage is applied to the Ignition Load Relay
(K127). The relay is energized, 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 energized, applying ground to terminal
35 of the Engine Control Module (ECM) (Z132),
signalling 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 energized, 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 relay is energized, applying battery voltage to
the Engine Control Module (ECM) (Z132),
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–energizes, removing the ground supply from
terminal 35 of the Engine Control Module (ECM)
(Z132), signalling 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–energizes,
removing battery voltage from the Compressor
Clutch (K107), disengaging the Compressor.
signalling 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 energized, 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–energizes, removing battery voltage from the
Engine Control Module (ECM) (Z132), signalling
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–energizes, removing battery
voltage from the Compressor Clutch (K107),
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
E L E C T R I C A L T R O U B L E S H O O T I N G M A N U A L
1
| Categories | Land Rover, Land Rover Discovery |
|---|---|
| Tags | Land Rover |
| Model Year | 1995 |
| Download File |
|
| Document Type | Electrical Troubleshooting Manual |
| Language | English |
| Product Name | Discovery |
| Product Brand | Land Rover |
| Document File Type | |
| Publisher | landrover.com |
| Wikipedia's Page | http://en.wikipedia.org/wiki/Land_Rover |
| Copyright | Attribution Non-commercial |
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