Dodge 1997 Neon WIRING DIAGRAMS, Owner'S Manual

Page: 115 / 256

8W-42 AIR CONDITIONING-HEATER
INDEX
page page
DESCRIPTION AND OPERATION
A/C OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . 6
AIR CONDITIONING-HEATER SYSTEM . . . . . . . 6
BLOWER MOTOR OPERATION . . . . . . . . . . . . . 6
HELPFUL INFORMATION . . . . . . . . . . . . . . . . . . 7
RADIATOR FAN OPERATION . . . . . . . . . . . . . . . 6
DESCRIPTION AND OPERATION
AIR CONDITIONING-HEATER SYSTEM
The A/C-Heater System is powered by a by several
fuses. Fuse 10, a 15 amp fuse located in the fuse
block, is HOT in the RUN position. This fuse powers
the coil side of the A/C compressor clutch relay
located in the Power Distribution Center (PDC).
A 30 amp fuse, on circuit A16 located in the PDC,
powers the solid state radiator fan relay. This fuse is
HOT at all times. The 10 amp fuse on circuit A17
located in the PDC powers the contact side of the A/C
compressor clutch relay.
The A/C-Heater blower motor is protected by a 25
amp fuse located in cavity 7 of the fuse block. This
fuse in HOT in the RUN position only. When the
ignition switch is in the RUN position, power is sup-
plied to the fuse on circuit A22. The power leaves the
fuse on circuit C1 and goes directly to the blower
motor.
There is a 4 amp fuse located in cavity 12 of the
fuse block used for the illumination lamps in the A/C-
Heater control. The fuse is HOT at all times.
A/C OPERATION
When the A/C or the defrost switch is put in the
ON position, and the A/C cycling switch, low pressure
cut-out switch, and the high pressure switch are
CLOSED, the Powertrain Control Module (PCM)
receives a request for A/C.
After receiving this input, the PCM activates the
A/C compressor by grounding the C28 circuit on the
coil side of the A/C Compressor Clutch relay. Power
for the coil side of the relay is supplied on the bus
bar located in the Power Distribution Center (PDC).
With the coil energized, current flows from the 10
amp fuse in the PDC on circuit A17 through the
CLOSED contacts in the relay, on the C3 circuit to
the A/C compressor clutch.
The A/C compressor clutch receives this voltage
and creates a magnetic field energizing the clutch.
Ground for the coil is provided at the right headlamp
ground.
The connector at the A/C compressor has a diode
located in it. This diode is used to control the induced
voltage resulting from the magnetic field collapsing
when the clutch is disengaged. The diode provides a
path for the voltage to protect other components and
systems.
The A/C compressor clutch relay is also used by the
PCM to disengage the compressor in a Wide Open
Throttle (W.O.T.) condition.
RADIATOR FAN OPERATION
The radiator fan system used in this vehicle uses a
solid state relay that controls the speed of the radia-
tor fan.
Power for the relay is supplied on circuit A16 This
circuit is HOT at all times and protected by a 30 amp
fuse located in the Power Distribution Center (PDC).
Ground for the coil side of the relay is controlled by
the Powertrain Control Module (PCM). When the
PCM determines the need for fan operation the PCM
supplies the ground path for circuit K173. This cir-
cuit connects to cavity 18 of the PCM connector.
From the relay circuit C25 connects to the radiator
fan motor(s). On vehicles equipped with the manual
transmission only one radiator fan is used. For vehi-
cles equipped with an automatic transmission there
are two radiator fans used.
Ground for the radiator fans is supplied on circuit
Z1.
BLOWER MOTOR OPERATION
With the ignition switch in the RUN position,
power flows from the 25 amp fuse, in cavity 7 of the
fuse block, to the blower motor. Blower motor speed
is controlled by the fan control switch located in the
instrument panel, and the resistor block.
Blower motor LOW speed operation is accom-
plished on the C4 circuit. When the control switch is
moved to the LOW speed position, current is passed
on the C7 circuit through the blower motor resistor
to the C4 circuit. It then flows through the blower
motor switch to the Z8 circuit. The Z8 circuit termi-
nates at a grounding point on the instrument panel
left center support.
The operation of the blower motor M1 and M2
speed operations is the same as the LOW speed
8W - 42 - 6 8W - 42 AIR CONDITIONING-HEATER
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