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SECTION 7D

AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM

Caution : Disconnect the negative battery cable before removing or installing any electrical unit or when a tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.

SPECIFICATIONS

Fastener Tightening Specifications

Application
N•m
Lb-Ft
Lb-In
Air Filter Cover Nut
4
-
35
Ambient Air Temperature Retaining Bracket Nut
6
-
53
Blower Motor Resistor Screws
6
-
53
Control Assembly Retaining Screws
2.5
-
22
Expansion Valve Bolts
10
-
89
Heater/Air Distributor Assembly Case Screws
8
-
71
Liquid Evaporator Pipe Retaining Nuts
10
-
89
Suction Hose Retaining Nuts
10
-
89

SCHEMATIC AND ROUTING DIAGRAMS

A/C Sensors and Defoggers Diagram


C7A17D01
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A/C Blower and Motor Controls Diagram


C7A17D02
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A/C Compressor Controls Diagram


C7A17D03
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Connector End View


C7A17D18
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A1
Power Ground
B6
Duct temp sensor signal
A2
Temperature motor control
B7
EVAP core temp sensor signal
A3
-
B8
Sun load sensor signal
A4
Controller illumination (BCM)
B9
APS signal
A5
IGN II (15A)
B10
-
A6
Defog relay
B11
Temperature motor 5V ref
A7
Communication between ECM
B12
Temperature motor signal
A8
Temperature motor control
B13
Temperature motor ground
A9
-
B14
-
A10
-
B15
Power module (speed signal)
A11
Intake motor control
B16
Intake motor 5v Ref
A12
Intake motor control
B17
Intake motor signal
A13
Blower high relay ground control
B18
Intake motor ground
A14
Fuse "F19" (BAT)
B19
Mode motor control
A15
-
B20
Mode motor control
A16
Duct temp/EVAP core temp ground
B21
Mode motor 5V Ref
B1
Power module (speed control)
B22
Mode motor signal
B2
-
B23
Mode motor ground
B3
Single wire CAN
B24
-
B4
-
B25
-
B5
-
B26
-

DIAGNOSIS

General A/C Diagnostics

Refer to Section 7B, Manual Control Heating, Ventilation, and Air Conditioning System for details of the following procedures:

C7A17D04
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Automatic Temperature Controller Does Not Operate When Ignition Is ON

StepActionValue(s)YesNo
1
Check the fuse Ef2.
Is fuse Ef2 blown?
-
Go to Step 2
Go to Step 3
2
Replace fuse Ef2.
Is the repair complete?
-
System OK
-
3
  1. Remove the controller.
  2. Measure the voltage between connectors A14.
Is the voltage within the specified value?
11-14 v
Go to Step 4
Go to Step 5
4
  1. Check the controller for damage.
  2. Replace the controller if it is damaged.
Is the repair complete?
-
System OK
-
5
Check the voltage between terminal A1 and ground.
Is this voltage as specified?
0 v
Go to Step 6
Go to Step 7
6
  1. Check the wiring harness between fuse F19 and the terminal A14 for damage.
  2. Replace the wiring harness if it is damaged.
Is the repair complete?
-
System OK
-
7
  1. Check the wiring harness between terminal A14 and ground G203 for damage.
  2. Repair the wiring harness, or ground connection as required.
Is the repair complete?
-
System OK
-

C7A17D05
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Controller Does Not Illuminate When Light Switch Is ON

StepActionValue(s)YesNo
1
Check other instrumentation lights.
Are those lights also off?
-
Go to Step 2
2
  1. Remove the controller.
  2. Check the voltage between terminals A4 of the controller connector.
Is the voltage within the specified value?
11-14 v
Go to Step 4
Go to Step 3
3
Repair the wiring harness between J6 terminal 3 and controller connector terminal A4.
Is the repair complete?
-
System OK
-
4
Check the illumination lamps.
Is one burned out?
-
Go to Step 5
Go to Step 6
5
Replace the burned out illumination lamp.
Is the repair complete?
-
System OK
-
6
Replace the ATC controller.
Is the repair complete?
-
System OK
-

C7A17D06
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Blower Motor Does Not Run At All

StepActionValue(s)YesNo
1
  1. Turn the ignition to ON.
  2. Observe the temperature indication screen of the controller.
Does the digit go on and off?
-
Go to Step 2
Go to Step 3
2
Run a self-diagnosis circuit check.
Does the display indicate a defect code?
-
Go to the table for the code that flashes.
-
3
Check fuse F18 in the I/P fuse block.
Is this fuse in good condition?
-
Go to Step 5
Go to Step 4
4
Replace fuse F18.
Is the repair complete?
-
System OK
-
5
  1. Turn the ignition switch to ON.
  2. Measure the voltage between ground and terminal 85(BRM) of the blower relay.
Is the voltage within the specified value?
11-14 v
Go to Step 15
Go to Step 8
6
Measure the voltage between ground and terminal 30 (BRN/WHT) at the blower relay.
Is the voltage within the specified value?
11-14 v
Go to Step 8
Go to Step 7
7
Repair any problem found in terminal 85 at the relay connector, or ground G203.
Is the repair complete?
-
System OK
-
8
Replace the blower relay.
Is the repair complete?
-
System OK
-
9
  1. Turn the ignition switch to OFF.
  2. Disconnect the wiring harness at the blower motor.
  3. Turn the ignition switch to ON.
  4. Measure voltage between ground and blower connector 2.
Is the voltage within the specified value?
11-14 v
Go to Step 11
Go to Step 10
10
  1. Turn the ignition switch to OFF.
  2. Check circuit YEL between blower connector terminal 2 and blower relay terminal 30.
  3. Repair any problem found in the wiring or a connector terminal at the blower connector, connector J209, or the blower relay socket.
Is the repair complete?
-
System OK
-
11
Measure the resistance between the connector terminals on the blower motor.
Does the resistance match the specified value?
≈ 5 Ω
Go to Step 13
Go to Step 12
12
Replace the blower motor.
Is the repair complete?
-
System OK
-
13
Measure the resistance of circuit between terminal 1 of the blower connector and terminal 30 of the Max HI relay and terminal 2 of the power module.
Does the resistance match the specified value?
≈ 0 Ω
Go to Step 15
Go to Step 14
14
Repair the problem in circuit.
Is the repair complete?
-
System OK
-
15
Measure the resistance of circuit from terminal 4 of the power module connector to ground.
Does the resistance match the specified value?
0 Ω
Go to Step 17
Go to Step 16
16
  1. Trace circuit from terminal 4 of the power module connector and terminal 87 of the Max HI relay to ground G203.
  2. Repair any problem found in the wiring, ground G203.
Is the repair complete?
-
System OK
-
17
Replace the ATC controller.
the repair complete?
-
System OK
-

Air Source Selection Not Controlled

Refer to "A/C Blower and Motor Controls Diagram" for the electrical schematic diagram of the circuits described in this procedure.

Air Source Selection Not Controlled

StepActionValue(s)YesNo
1
Measure the voltage at terminal 4 of the intake motor.
Is the voltage within the value specified?
11-14 v
Go to Step 3
Go to Step 2
2
  1. Check the connector and circuit BRN for any wiring or terminal problems.
  2. Repair any problems found.
Is the repair complete?
-
System OK
-
3
  1. Using the Intake Motor Table, measure the voltages at the specified terminals of the motor connector.
  2. Change the intake setting and observe the voltage changes.
Are these voltages within the specified value?
See the "Intake Motor Table"
Go to Step 4
Go to Step 5
4
Replace the intake motor.
Is the repair complete?
-
System OK
-
5
  1. Using the Intake Motor Table, measure the voltages at the specified terminals of the controller connector.
  2. Change the intake setting and observe the voltage changes.
Are these voltages within the specified value?
See the "Intake Motor Table"
Go to Step 6
Go to Step 7
6
  1. Check the wiring harness and connectors between the controller and the motor that is not performing properly.
  2. Repair or replace the wiring harness or the defective terminal.
Is the repair complete?
-
System OK
-
7
Check the connector at the controller.
Is there a defective terminal?
-
Go to Step 8
Go to Step 9
8
Repair or replace the terminal.
Is the repair complete?
-
System OK
-
9
Replace the controller.
Is the repair complete?
-
System OK
-

Intake Control Table

Intake Setting
Intake Motor
.
Connector Terminal
Controller/Motor
Controller/Motor
Controller/Motor
B14/7
A15/6
B13/5
Recirculate
0 v
11-14 v
11-14 v
1/3 Fresh
11-14 v
0 v
11-14 v
Fresh
11-14 v
11-14 v
0 v

Compressor Magnetic Clutch Does Not Engage

Refer to "A/C Compressor Controls, SOHC" or "A/C Compressor Controls, DOHC" for the electrical schematic diagram of the circuits described in this procedure.

Compressor Magnetic Clutch Does not Engage

StepActionValue(s)YesNo
1
  1. Remove the ATC Controller from the instrument panel, keeping the wiring harness connected.
  2. Turn the ignition switch to ON.
  3. Turn the A/C switch to ON.
  4. Check the voltage between ground and terminal A7of J1 on the controller.
Is the voltage within the specified value?
11-14 v
Go to Step 2
2
Replace the ATC controller.
Is the repair complete?
-
System OK
-


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