Opel Frontera UE. Manual - part 1246

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

1A–105

• Pressing the DEF mode switch automatically turns on

the compressor.

C01RY00010

Heating Start Timing Control

When the automatic air conditioner is started, heating is
turned on only when the coolant temperature detected
by the coolant temperature sensor is 18

°

C or less and

total signal derived from the sensor signals has
detected that the heating condition is met.
If the coolant temperature detected by the sensor is
18

°

C or less, 4.5V is set for the blower fan motor

terminal voltage and the DEF is selected for the blow
port mode.
When the temperature detected by the sensor is above
18

°

C, the blow port mode is switched to the Auto

Control and the voltage across the blower fan motor
terminal is linearly increased from 4.5V to auto control
voltage (auto airflow).

840RX015

Cooling Start Timing Control

When the automatic air conditioner is started, cooling is
turned on only when the temperature detected by the
interior temperature sensor is 30

°

C or above and the

total signal derived from the sensor signals has
detected that the cooling condition is met.
When the cooling condition has been met, the fan
voltage across the blower fan motor terminal is set to
4.5V for 7 seconds maximum, then it is linearly
increased up to the auto airflow level at the rate of 0.6V/
sec.

C06RX003

SECTION

1A–106

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Troubleshooting

Troubleshooting, Its Overview and Procedures

The automatic heater and air conditioner equips with
the “Self-Diagnosis Function" to check its major
components.
This function makes access to the sensors, actuators
and blower fan motor system easier when checking
them up and, when a failed part is located, this function
restores its original performance.
When implementing the troubleshooting, this
self-diagnosis function narrows the range to be

searched at the first step, then check relevant parts one
by one according to the “Checking Procedures by Failed
Location".  As for a location this function is
unappreciable, the system accurately determines
characteristics of a given trouble and checks relevant
parts according to the “Checking Procedures by Failed
Location".
The following illustrates basic troubleshooting flow.

Basic Troubleshooting Flow

F01RX009

SECTION

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

1A–107

Auto Air Conditioner Control Unit Power Supply Diagnosis

This check is required because a trouble on the auto
amplifier (control unit) power supply circuit or grounding
circuit prevents accurate troubleshooting.

D08R100120

Condition

Possible cause

Correction

Power source does not supply to auto
air conditioner control unit.

—

Refer to Chart A

SECTION

1A–108

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Chart “A": Check of Auto Amplifier Power Supply System

Step

Action

Value(s)

Yes

No

1 

Is the fuse C–5 normal?

—

Go to Step 2

Replace the 

fuse

2 

Is the fuse F–5 normal?

—

Go to Step 3

Replace the 

fuse

3 

Disconnect the auto A/C control unit connector I–20.   
Is the battery voltage applied between the harness
side connector terminal No.I20–8 and the ground?

Approx. 12V

Go to Step 5

Go to Step 4

4 

Repair an open circuit between the fuse C–5 and
terminal No.I20–8.   
Is the action complete?

—

Go to Step 4

—

5 

Is there continuity between the harness side
connector terminal No.I20–16 and the ground?

—

Go to Step 7

Go to Step 6

6 

Repair an open circuit between terminal No.I20–16
and the ground No.B–6.
Is the action complete?

—

Go to Step 5

—

7 

Is there continuity between the harness side
connector terminal No.I20–9 and the ground?

—

Go to Step 9

Go to Step 8

8 

Repair an open circuit between terminal No.I20–9 and
the ground No.B–8.
Is the action complete?

—

Go to Step 7

—

9 

Turn the lighting switch on.
Is the battery voltage applied between the harness
side connector terminal No.I20–10 and the ground?

Approx. 12V

Go to Step 11

Go to Step 10

10 

Repair an open circuit between the lighting switch and
terminal No.I20–10.
Is the action complete?

—

Go to Step 9

—

11 

Turn the starter switch on.
Is the battery voltage applied between the harness
side connector terminal No.I20–7 and the ground?

Approx. 12V

—

Go to Step 12

12 

Repair an open circuit between the fuse F–5 and
terminal No.I20–7.
Is the action complete?

—

Verify repair

—

SECTION