JEEP CHEROKEE 1995 Service Repair Manual

AIR CONDITIONING/HEATER
CONTENTS
page page
HEATER AND AIR CONDITIONING........... 2 HEATERSYSTEM......................... 1
GENERAL INFORMATION
This section of the wiring diagrams is divided into
two sub-sections; Heater, and A/C-Heater. When re-
ferring to the circuit descriptions or wiring diagrams,
ensure that you use the correct sub-section.
HEATER SYSTEM
HEATER
In the RUN position, the ignition switch connects
circuit A1 from fuse 4 in the Power Distribution Cen-
ter (PDC) to circuit A22. Circuit A22 powers a bus
bar in the fuse block that supplies voltage to circuit
C1 through fuse 12.
A heater-off switch in circuit C1 opens when the
heater controls are in the VENT position. When the
heater-off switch closes, circuit C1 supplies battery
voltage to the blower motor switch. The switch sets
blower motor speed to HIGH, MEDIUM, LOW or
OFF.
The switch connects to the blower motor resistor
block in the LOW and MEDIUM positions and di-
rectly to the blower motor in the HIGH position. The
resistor block contains two resistors connected in se-
ries. Circuit C7 connects the resistor block to the
blower motor.
From the blower motor resistor block, circuit C7 is
double crimped at the HIGH terminal of the blower
motor switch. Circuit C7 continues to the blower mo-
tor from the blower motor switch.
When the blower motor switch is in the LOW posi-
tion, it supplies voltage to the resistor block on cir-
cuit C4. From circuit C4, voltage passes through both
resistors in the resistor block to the blower motor on
circuit C7.In the MEDIUM position, the blower motor sup-
plies voltage to the resistor block on circuit C5. From
circuit C5 voltage flows through one resistor to the
blower motor on circuit C7.
In the HIGH position, the blower motor switch con-
nects directly to the blower motor on circuit C7. Volt-
age does not pass through the resistor block.
Circuit Z1 provides ground for the blower motor.
HELPFUL INFORMATION
²Check fuse 4 in the PDC.
²Check fuse 12 in the fuse block.
DIAGRAM INDEX
Component Page
Blower Motor...........................8W-42-3
Blower Motor Resistor.....................8W-42-3
Blower Motor Switch......................8W-42-3
Fuse 4 (PDC)...........................8W-42-3
Fuse 12 (Fuse Block)......................8W-42-3
Heater Switch...........................8W-42-3
Ignition Switch..........................8W-42-3
J8W-42 AIR CONDITIONING/HEATERÐYJ VEHICLES 8W - 42 - 1

AIR CONDITIONING AND HEATER
GENERAL INFORMATION
On vehicles built with the 2.5L engine, the electri-
cal system has provisions for dealer installed air con-
ditioning. The provisions consist of two connectors
which include circuitry for:
²Circuit C1 - Ignition feed
²Circuit C21 - Blower motor switch
²Circuit C91 - A/C request signal
²Circuit C20 - A/C select signal
²Circuit C13 - Ground for coil side of A/C compres-
sor clutch relay
²Circuit G5 - Battery voltage for coil side of A/C
compressor clutch relay
A/C COMPRESSOR
When the ignition switch is in the RUN position it
connects circuit A1 from fuse 4 in the Power Distri-
bution Center (PDC) to circuit A22. Circuit A22 sup-
plies battery voltage to fuse 12 in the fuse block.
Fuse 12 powers circuit C1.
Circuit C1 supplies battery voltage to the A/C
blower switch. Circuit C21 connects the A/C blower
switch to the A/C low pressure switch.
When the operator selects A/C operation, the A/C
blower switch provides the A/C request signal to cav-
ity 27 of the Powertrain Control Module (PCM) on
circuit C91. At the same time, the blower switch sup-
plies voltage through the A/C thermostat to circuit
C21.
Circuit C21 supplies voltage to the A/C low pres-
sure switch. When the A/C low pressure switch
closes, circuit C20 provides battery voltage to the
contact side of the A/C compressor clutch relay and
provides the A/C select signal to the PCM. Circuit
C20 is double crimped at the contact side of the re-
lay. The C20 circuit branch from the relay supplies
the A/C select input to cavity 28 of the PCM.
After receiving the A/C request signal, the PCM en-
ergizes the A/C compressor clutch relay by providing
ground for the coil side of the relay on circuit C13.
Circuit C13 connects to cavity 34 of the PCM.
Circuit G5 from fuse 9 in the fuse block supplies
voltage to the coil side of the relay. In the START or
RUN positions the ignition switch connects circuit A1
from fuse 4 in the PDC with circuit A21. Circuit A21
connects to the fuse block bus bar that powers circuit
C5 through fuse 9.
When the PCM energizes the A/C compressor
clutch relay, the relay switches from its normally
grounded position to connect circuit C20 to circuit
C3. Circuit C3 supplies voltage to the case grounded
A/C compressor clutch.
HELPFUL INFORMATION
²Circuit G5 is double crimped at the coil side of the
A/C compressor clutch relay. The G5 branch from the
relay continues to the back-up lamp switch.
²Circuit Z1 provides ground for the A/C compressor
clutch relay when the relay is in its normally
grounded position.
A/C-HEATER BLOWER MOTOR
When the ignition switch is in the RUN position it
connects circuit A1 from fuse 4 in the Power Distri-
bution Center (PDC) to circuit A22. Circuit A22 sup-
plies battery voltage to fuse 12 in the fuse block.
Fuse 12 powers circuit C1.
Circuit C1 supplies battery voltage to the A/C
blower switch. In the LOW position, the A/C blower
switch supplies voltage to the low speed brush of the
blower motor. In the MEDIUM position, the switch
supplies voltage to the medium speed bush of the
blower motor. In the HIGH position, the switch sup-
plies voltage to the high speed brush of the blower
motor.
The blower motor has a field jumper. The ground
circuit for the blower motor connects to the cigar
lighter. Circuit Z1 provides ground for the blower mo-
tor and the cigar lighter.
HELPFUL INFORMATION
²Check fuse 4 in the PDC.
²Check fuse 12 in the fuse block.
DIAGRAM INDEX
Component Page
A/C Compressor Clutch.....................8W-42-4
A/C Compressor Clutch Relay................8W-42-4
A/C Thermostat..........................8W-42-5
Blower Motor...........................8W-42-5
Blower Motor Switch......................8W-42-5
Fuse 4 (PDC).........................8W-42-4, 6
Fuse 7 (Fuse Block).......................8W-42-6
Fuse 9 (Fuse Block).....................8W-42-4, 6
Fuse 12 (Fuse Block)....................8W-42-4, 6
Ignition Switch........................8W-42-4, 6
Powertrain Control Module.................8W-42-4, 6
8W - 42 - 2 8W-42 AIR CONDITIONING/HEATERÐYJ VEHICLESJ

INTERIOR LIGHTING
INDEX
page page
Accessory Lamp and Heater Control Panel Lamp . . 1
Combination Buzzer........................ 1
Courtesy Lamps and Dome Lamps............. 1
Diagram Index............................ 2General Information........................ 1
Transmission Range Lamp................... 1
Underhood Lamp.......................... 1
GENERAL INFORMATION
Circuit M1 supplies power to the underhood lamp,
dome lamp, right courtesy lamp and left courtesy
lamp. Fuse 12 in the Power Distribution Center
(PDC) protects circuit M1. Circuit A4 from fuse 8 in
the PDC supplies voltage to fuse 12 and circuit M1.
Fuse 12 is referred to as the Ignition Off Draw (IOD)
fuse.
COURTESY LAMPS AND DOME LAMPS
Circuit M1 supplies battery voltage to the dome
lamps and the right and left courtesy lamps. Circuit
M2 provides ground for the lamps through either the
case grounded door jamb switches or through the
dimmer switch to circuit Z1.
In the ON position, the dimmer switch connects
circuit M2 to ground on circuit Z1. When a door
opens, the case grounded door jamb switch closes and
provides ground for the lamps on circuit M2.
HELPFUL INFORMATION
²Circuit M1 also supplies voltage for radio memory,
underhood lamp and the ABS data link connector.
UNDERHOOD LAMP
Circuit M1 supplies battery voltage for the under-
hood lamp. A mercury switch in series after the lamp
connects the lamp to ground on circuit Z1. When the
hood is raised, mercury inside the switch moves to a
position where it connects circuit M1 to circuit Z1, il-
luminating the lamp. The underhood lamp is wired
in parallel with other components on circuit M1.
ACCESSORY LAMP AND HEATER CONTROL PANEL
LAMP
Circuit E1 from the dimmer switch supplies bat-
tery voltage to fuse 10 in the fuse block when the
dimmer switch is in the LOW or ON position. Fuse
10 protects circuit E2 which supplies power to the
heater control panel lamp and the accessory lamp.
Circuit Z1 provides ground for each lamp.
TRANSMISSION RANGE LAMP
Circuit E1 from the dimmer switch supplies bat-
tery voltage to fuse 10 in the fuse block when thedimmer switch is in the LOW or ON positions. Fuse
10 protects circuit E2 which supplies power to the
transmission range lamp. The lamp is case grounded.
COMBINATION BUZZER
The combination buzzer module sounds an audible
warning tone. The tone sounds for seat belt warning
and when the key is in the ignition switch while the
drivers door is open. The tone also sounds when the
ignition switch is in the ON position while the driv-
ers side seat belt is not buckled. Refer to Group 8U
for buzzer operation.
Fuses 3 and 9 in the fuse block protect the combi-
nation buzzer. Fuse 3 powers circuit F32 which con-
nects to the buzzer. Circuit A6 from fuse 3 in the
Power Distribution Center (PDC) supplies power to
the fuse block for circuit F32.
Circuit G5 from fuse 9 also provides voltage to the
combination buzzer when the ignition switch is in
the START or RUN position. The ignition switch con-
nects circuit A1 from fuse 4 in the PDC to circuit
A21. Circuit A21 connects to the fuse block.
When the key-in switch closes, it connects circuit
G26 to circuit G16. Circuit G16 connects to the driv-
ers side door jamb switch. When the drivers side door
is open and the key-in switch is closed, the case
grounded door jamb switch closes and supplies
ground for the buzzer. Circuit G26 from the combina-
tion buzzer connects to the key-in switch.
Circuit G13 form the buzzer powers the seat belt
warning lamp in the instrument cluster. Circuit Z1
at the instrument cluster provides ground for the
lamp.
Circuit G10 from the buzzer connects to the seat
belt switch. When the seat belt is unlatched, the seat
belt switch closes providing ground on circuit Z1.
Circuit Z1 also grounds the combination buzzer
module.
HELPFUL INFORMATION
²Circuit F32 also powers the stop lamp switch.
²Circuit G5 also provides power for the instrument
cluster gauges and warning lamps, heated rear win-
dow relay and A/C compressor clutch relay. On Cana-
J8W-44 INTERIOR LIGHTINGÐYJ VEHICLES 8W - 44 - 1

dian vehicles, circuit G5 also powers the Daytime
Running Lamps (DRL) module.DIAGRAM INDEX
Component Page
Combination Buzzer.......................8W-44-5
Courtesy Lamps.........................8W-44-4
Dome Lamps...........................8W-44-4
Door Jamb Switches......................8W-44-4
Fuse 3 (Fuse Block).......................8W-44-5
Fuse 3 (PDC).........................8W-44-3, 5
Fuse 4 (PDC)...........................8W-44-5
Fuse 8 (Fuse Block).......................8W-44-3
Fuse 8 (PDC)...........................8W-44-4
Fuse 9 (Fuse Block).......................8W-44-5
Fuse 10 (Fuse Block)......................8W-44-3
Fuse 12 (PDC)..........................8W-44-4
Headlamp Switch.........................8W-44-3
Ignition Switch..........................8W-44-5
Illumination Lamps.......................8W-44-3
Key-In Switch...........................8W-44-5
Panel Lamp Dimmer Switch................8W-44-3, 4
Seat Belt Switch.........................8W-44-5
Underhood Lamp.........................8W-44-4
8W - 44 - 2 8W-44 INTERIOR LIGHTINGÐYJ VEHICLESJ