Chrysler PT Cruiser Service & Repair Manual page 1974

24 - 68 HEATING & AIR COND. - RHD
A/C COMPRESSOR CLUTCH RELAY (Continued)
OPERATION
The A/C compressor clutch relay is an electrome-
chanical switch that uses a low current input from
the Powertrain Control Module (PCM) to control the
high current output to the Compressor clutch electro-
magnetic coil. The movable common feed contact
point is held against the fixed normally closed con-
tact point by spring pressure. When the relay coil is
energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-
mally closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-
able contact point back against the fixed normally
closed contact point. The resistor or diode is con-
nected in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-
netic field of the relay coil collapses.
The A/C compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the PDC. The inputs and outputs of the
A/C compressor clutch relay include:
• The common feed terminal (30) receives a bat-
tery current input from a fuse in the PDC through a
fused B(+) circuit at all times.
• The coil ground terminal (85) receives a ground
input from the PCM through the A/C compressor
clutch relay control circuit only when the PCM elec-
tronically pulls the control circuit to ground.
• The coil battery terminal (86) receives a battery
current input from a fuse in the fuse block module
through a fused ignition switch output (run-start) cir-
cuit only when the ignition switch is in the On or
Start positions.
• The normally open terminal (87) provides a bat-
tery current output to the compressor clutch coil
through the A/C compressor clutch relay output cir-
cuit only when the A/C compressor clutch relay coil is
energized.
• The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the A/C compres-
sor clutch relay coil is de-energized.
Refer to the appropriate wiring information for
complete air conditioning-heater wiring diagrams.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 6).
Fig. 6 Power Distribution Center (PDC)
1 - PDC
(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for A/C compressor
clutch relay identification and location.
(4) Remove the A/C compressor clutch relay from
the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper A/C
compressor clutch relay location.
(2) Position the A/C compressor clutch relay in the
proper receptacle in the PDC.
(3) Align the A/C compressor clutch relay termi-
nals with the terminal cavities in the PDC recepta-
cle.
(4) Push down firmly on the A/C compressor clutch
relay until the terminals are fully seated in the ter-
minal cavities in the PDC receptacle.
(5) Install the cover onto the PDC.
(6) Reconnect the battery negative cable.
PT