A/c-Heater System - Automatic Isuzu Impulse I

A/C SYSTEM SPECIFICATIONS

A/C SYSTEM SPECIFICATIONS

DESCRIPTION

The Isuzu Impulse uses an automatic A/C-heater system. The A/C system consists of 5 main units: an evaporator, compressor, condenser, receiver-drier, and expansion valve. The heater system consists of a thermostat, 3 electrically controlled heater unit actuators, ducting and a heater core.

The automatic portion of the system consists of, a satellite switch, in-car sensor, sun sensor, ambient sensor, potentiometer, and an electrically controlled blend door actuator. The system allows selection of an in-car temperature range of 65-85°F (18-29°C).

The automatic system can be overridden manually. Three blower motor speeds can be obtained: low, medium and high. These speeds are controlled automatically with the system in automatic mode. The electrically controlled blend door mixes cold and hot air to vary the temperature of air output.

Temperature & Blower Control Power Circuit

1. See if voltage exists between control unit chassis harness side connector terminal No. 154 and ground.
2. If there is voltage, check for open circuit between control unit chassis harness side connector terminal No. 292 and ground. If there is no open, no trouble exists. If an open exists, repair harness between terminal and ground.
3. If no voltage exists in step 1), check to see if fuse No. 6 has failed. Replace fuse if blown. If fuse is okay, see if voltage is present between fuse and ground. If voltage is present, repair harness between fuse and terminal. If no voltage exists, replace power source circuit to fuse.

Mode Control Power Circuit

1. See if voltage is present between control unit chassis harness side connector terminal No. 162 and ground.
2. If no voltage exists, check to see if fuse No. 4 has failed. If fuse is blown, replace fuse. If fuse is not blown, see if voltage is present between fuse and ground. If no voltage is present, repair power source circuit to fuse. If there is voltage, repair harness between fuse and terminal.
3. If voltage exists in step 1), see if voltage is present between control unit chassis harness side connector terminal No. 151 and ground.
4. If voltage is present, check for an open circuit between satellite switch chassis harness side connector terminal No. 165 and ground. If no open is present, there is no trouble. If an open exists, repair harness between terminal and ground.
5. If no voltage is present in step 3), check to see if fuse No. 6 has failed. If fuse has blown, replace fuse. If fuse is okay, see if voltage is present between fuse and ground. If there is, repair harness between fuse and terminal. If there is no voltage, repair power source circuit to fuse.

Air-Source Cannot Be Switched (Part 1 of 2). Scheme 1

Air-Source Cannot Be Switched (Part 2 of 2). Scheme 2

Air Delivery Mode Cannot Be Switched. Scheme 3

Magnetic Clutch Inoperative - G200Z Engine (Part 1 of 2). Scheme 4

Magnetic Clutch Inoperative - G200Z Engine (Part 2 of 2). Scheme 5

Magnetic Clutch Inoperative - 4ZC1 Engine (Part 1 of 4). Scheme 6

Magnetic Clutch Inoperative - 4ZC1 Engine (Part 2 of 2). Scheme 7

Magnetic Clutch Inoperative - 4ZC1 Engine (Part 3 of 4). Scheme 8

Magnetic Clutch Inoperative - 4ZC1 Engine (Part 4 of 4). Scheme 9

Blower Motor Does Not Operate in "3" Position (Part 1 of 2). Scheme 10

Blower Motor Does Not Operate in "3" Position (Part 2 of 2). Scheme 11

Temperature Cannot Be Controlled. Scheme 12

Blower Motor Does Not Operate in "AUTO" Position. Scheme 13

Blower At Maximum Even in "OFF" Position. Scheme 14

Blower Motor Does Not Operate in "1" or "2" Position. Scheme 15

Blower Motor Operates Only in "3" Position. Scheme 16

Removal

Disconnect tubes from receiver-drier. Disconnect hose from condenser tube. Remove 4 nuts attaching condenser to radiator support. Remove condenser assembly from vehicle.

Installation

To install, reverse removal procedure.

Removing Condenser and Receiver-Drier. Scheme 17

COMPRESSOR

Note. Before removing distributor, make setting marks for reference at reassembly.

Remove distributor. Disconnect high and low pressure tubes at evaporator core. Remove compressor belt and idler pulley. Remove bolts attaching compressor to mounting bracket. Disconnect compressor clutch wiring. Remove compressor assembly.

To install, reverse removal procedure.

Scheme 18

1. Open glove box. Unhook glove box stay from slot in upper cover by lift up on stay and pulling outward. Remove glove box and glove box upper cover. Remove steering wheel. Remove lap vent grill assembly. Remove gauge upper hood.
2. Remove gauge, switch and satellite assembly. Remove front console assembly. Remove instrument panel front cover. Remove front pillar trim covers. Remove instrument panel grill. Remove instrument panel cover assembly. (Scheme 18): Removing Instrument Panel Assembly
3. Disconnect evaporator tubes at evaporator. Disconnect heater hoses at heater core. Remove evaporator assembly. Remove blower and heater units. Remove defroster duct.

To install, reverse removal procedure.

Removing Heater, Blower and Evaporator Assembly. Scheme 19

1. With heater, evaporator and blower assembly removed, remove evaporator power transistor and lining. Remove A/C relay and thermostat. Remove evaporator upper case. Remove evaporator lower case. Remove drain hose.
2. Remove evaporator upper, middle and lower grommets. Remove clip. Remove tube and "O" ring from expansion valve. Remove expansion valve and "O" ring. Remove evaporator core.

To install, reverse removal procedure.

Removing Evaporator Core. Scheme 20

Note. The components mentioned in this procedure are shown in numerical order.

1. With heater, evaporator and blower assembly removed, disconnect wire harness. Remove heater control unit. Remove heater unit actuator and 2 shutter levers. Remove resistor assembly. Remove control unit and wire harness. Remove actuator, actuator-to-lever rod, and lever.
2. Disconnect cable from lever and remove lever. Remove heater unit thermostat. Remove lever rod. Remove actuator. Remove actuator lever rod and shutter lever. Remove heater core plate and lining. Remove duct.
3. Remove side rear and side front case assemblies. Remove lining. Remove left and right case assembly. Remove center upper, center, and center lower shutter assemblies. Remove heater core assembly.

To install, reverse removal procedure.

Removing Heater Core. Scheme 21

WIRING DIAGRAMS

Note. Isuzu automatic A/C-heater systems wiring diagram is not available from manufacturer.