Mazda Training manual - part 294

AIR CONDITIONING 
06 - Symptom Troubleshooting

 

 

SG06-1

TC070-15-01H

 
Technician Name 
 
Symptom Troubleshooting [Manual Air Conditioner] 
 
 
Purpose: After completing this activity, you will be able to diagnose trouble cause by 
using Symptom based approach. 
 
What you will need to complete this activity: 
 

 

Current model vehicle  

 

Workshop Manual or Body Electrical Trouble Shooting Manual 

 

DVOM (Digital Volts/Ohm Meter) 

 
 
 

NOTE 

The purpose of this activity is to experience symptom troubleshooting to diagnose 
logically. Try not to find the defect setting by just guesswork. 

 
 

NOTE 

This activity sheets are designed based on Mazda 3 technical information. It’s 
recommended to provide Mazda 3. 

 

AIR CONDITIONING 
06 - Symptom Troubleshooting

 

 

SG06-2

TC070-15-01H

 
Troubleshooting Index 
 

No. 

 

TROUBLESHOOTING ITEM 

 

 

TROUBLESHOOTING ITEM 

 

1 

Insufficient air (or no air) blown from 
vents 

• Problem with each vent and/or duct 

2 

Amount of air blown from vents does 
not change. (Full-auto air conditioner) 

• Malfunction in blower system 

3 

Amount of air blown from vents does 
not change. (Manual air conditioner) 

• Malfunction in blower system 

4 

Air intake mode does not change. 

• Air intake mode does not change when 
switching REC/FRESH mode. 

5 

No temperature control with climate 
control unit 

• Malfunction in A/C unit and/or climate control 
unit air mix system 

6 

Windshield fogged. 

• A/C compressor does not operate while airflow
mode is in DEFROSTER or HEAT/DEF modes.

7 

Air from vents not cold enough 

• Magnetic clutch operates but A/C system 
malfunctions. 

8 

No cool air 

• Magnetic clutch does not operate. 
 

9 

Noise while operating A/C system 

• Noise from magnetic clutch, A/C compressor, 
hose or refrigerant line 

AIR CONDITIONING 
06 - Symptom Troubleshooting

 

 

SG06-3

TC070-15-01H

 
8 No cool air (DESCRIPTION: Magnetic clutch does not operate.) 
 
Among the nine troubleshooting items indicated on the previous page, we see the 
item No. 8 to learn how to diagnose Air Conditioner.  
 
 
Preparatory study 
 
As it’s given the description “Magnetic clutch does not operate”, the trouble is with an 
electrical/electronic device. See the Magnetic clutch circuit below. The magnetic 
clutch is activated when the PCM ground the coil inside the A/C relay to close the 
contact of the relay. Magnetic clutch is grounded through its body; an open circuit 
between Magnetic clutch and ground is unlikely occurred. If the magnetic clutch 
doesn’t operate with battery voltage applied through the A/C relay, the magnetic 
clutch may be faulty. Thermal protector inside the Magnetic clutch opens the circuit 
when its temperature is approximately 120 ºC or more. 
 

 

 
Look at the diagram above; predict the voltage at each terminal given in the table 
below during each status. 
 

Status 

Part name  Terminal 

IG switch OFF

IG switch ON 

PCM ground the coil 

inside A/C relay 

A 

        V  

        V  

        V  

E 

        V  

        V  

        V  

C 

        V  

        V  

        V  

 
 
A/C relay 
 

D 

        V  

        V  

        V  

Magnetic 
clutch 

A 

        V  

        V  

        V  

 
 
 
 
 

AIR CONDITIONING 
06 - Symptom Troubleshooting

 

 

SG06-4

TC070-15-01H

 
The figure below describes the A/C Compressor Control. The climate control unit 
sends an A/C signal to the PCM via the main fuse block and instrument cluster (PJB 
and instrument cluster) based on signals sent from the A/C switch, fan switch and 
evaporator temperature sensor. 
 

 

 
 
Chose the correct status or insert an appropriate number to complete the conditions 
that the PCM will close the circuit of the A/C relay to supply power activating the 
magnetic clutch. 
 

1. A/C switch:  ON / OFF.   
                  
2. Fan switch:  OFF position / Other than OFF position (1, 2, 3, or 4).    
                 
3. Evaporator temperature sensor:                        V or more 
                                                          (4.5 ºC or more) 
 
4. Refrigerant pressure switch:  ON / OFF. 

 (Between 0.2 and 3.0 MPa)  

 

Service Tip 

1. The LED on the A/C switch goes on when the switch is on. This proves the switch 

operates properly. However, it doesn’t exactly tell you the climate control unit 
receives the signal. 

2. If the blower motor activated with the Fan switch turned on, it proves the Fan 

switch is working properly.  

4. If there is no refrigerant, the Refrigerant pressure switch is off.