The compressor clutch and coil are the only serviced
parts on the compressor.
DIESEL ENGINE
The compressor clutch assembly consists of a sta-
tionery electromagnetic coil, a hub bearing and rotor
assembly, and a clutch plate (Fig. 5). The electromag-
netic coil and rotor are retained on the compressor
with snap rings. The clutch plate is mounted on the
compressor shaft and secured with a bolt.
The compressor is mounted on the left side of the
engine block behind the power steering pump. The
compressor is driven by a splined shaft off the rear of
the power steering pump. The splined shaft has a
drive flange mounted to it which attaches to a drive
spool. The spool links the compressor clutch plate to
the steering pump drive flange. When the clutch coil
is energized, it magnetically draws the clutch plate
into contact with the rotor and drives the compressor
shaft. When the coil is not energized, the rotor free-
wheels on the clutch hub bearing, which is part of
the rotor. The compressor clutch and coil are the only
serviced parts on the compressor.
COMPRESSOR CLUTCH RELAY
The compressor clutch relay is a International
Standards Organization (ISO) micro-relay. The termi-
nal designations and functions are the same as a con-
ventional
ISO
relay.
However,
the
micro-relay
terminal orientation (footprint) is different, the cur-
rent capacity is lower, and the relay case dimensions
are smaller than those of the conventional ISO relay.
The compressor clutch relay is a electromechanical
device that switches battery current to the compres-
sor clutch coil when the Powertrain Control Module
(PCM) grounds the coil side of the relay. The PCM
responds to inputs from the A/C compressor switch
on the heater-A/C control panel, the ATC controller,
the low pressure cycling clutch switch, and the high
pressure cut-off switch. See the Diagnosis and Test-
ing section of this group for more information on the
operation of the compressor clutch relay.
The compressor clutch relay is located in the Power
Distribution Center (PDC) in the engine compart-
ment. Refer to the PDC label for relay identification
and location.
The compressor clutch relay cannot be repaired
and, if faulty or damaged, it must be replaced.
CONDENSER
The condenser is located in front of the engine cool-
ing radiator. It is a heat exchanger that allows the
high-pressure refrigerant gas to give up its heat to
the air passing over the condenser fins. This causes
the refrigerant gas to condense into a high-pressure
liquid refrigerant.
The condenser cannot be repaired and, if faulty or
damaged, it must be replaced.
EVAPORATOR COIL
The evaporator coil is located in the heater-A/C
housing, under the instrument panel. Refrigerant
enters the evaporator as a low-temperature, low-
pressure liquid. As air passes over the fins of the
evaporator, the humidity in the air condenses on the
fins, and the heat from the air is absorbed by the
refrigerant. Heat absorption causes the refrigerant to
become a low-pressure gas before it leaves the evap-
orator.
The evaporator coil cannot be repaired and, if
faulty or damaged, it must be replaced.
FIXED ORIFICE TUBE
The fixed orifice tube is integral to the liquid line
located between the outlet tube of the condenser and
the inlet tube of the evaporator. The inlet and outlet
ends of the tube have a screen to filter the refriger-
Fig. 4 Compressor Clutch - Gasoline Engine
CLUTCH PLATE
SHAFT KEY
PULLEY
COIL
CLUTCH
SHIMS
SNAP RING
SNAP RING
Fig. 5 Compressor Clutch - Diesel Engine
COIL
CLUTCH ROTOR
CLUTCH PLATE
SNAP RING
SNAP RING
ZG
HEATING AND AIR CONDITIONING
24 - 7
DESCRIPTION AND OPERATION (Continued)
Summary of Contents for 1997 Grand Cherokee
Page 6: ...FASTENER IDENTIFICATION 4 INTRODUCTION ZG GENERAL INFORMATION Continued ...
Page 9: ...METRIC CONVERSION ZG INTRODUCTION 7 GENERAL INFORMATION Continued ...
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Page 286: ...7 12 COOLING SYSTEM ZG DIAGNOSIS AND TESTING Continued ...
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Page 1655: ...Fig 3 Oil Lubrication System ZG 5 2L ENGINE 9 57 DESCRIPTION AND OPERATION Continued ...
Page 1684: ...TORQUE 9 86 5 2L ENGINE ZG SPECIFICATIONS Continued ...
Page 1689: ...Fig 3 Oil Lubrication System ZG 5 9L ENGINE 9 91 DESCRIPTION AND OPERATION Continued ...
Page 1723: ...DIAGNOSIS AND TESTING SERVICE DIAGNOSIS DIESEL PERFORMANCE ZG ENGINE 9 3 ...
Page 1724: ...9 4 ENGINE ZG DIAGNOSIS AND TESTING Continued ...
Page 1725: ...ZG ENGINE 9 5 DIAGNOSIS AND TESTING Continued ...
Page 1726: ...9 6 ENGINE ZG DIAGNOSIS AND TESTING Continued ...
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Page 1762: ...SPECIFICATIONS ENGINE SPECIFICATIONS 9 42 ENGINE ZG ...
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Page 2122: ...DIAGNOSIS AND TESTING NV231 DIAGNOSIS 21 8 TRANSMISSION AND TRANSFER CASE ZG ...