Mazda MX-5 Miata (1997+). Manual - part 79

Disconnect A/C switch connector. Turn A/C switch on. Check continuity between indicated terminals. See A/C 
SWITCH TEST table. See Fig. 1 . Replace A/C switch if continuity is not as specified. 

A/C SWITCH TEST 

Fig. 1: Identifying A/C Switch Terminals 
Courtesy of MAZDA MOTORS CORP. 

A/C RELAY 

Remove relay. Check continuity between indicated relay terminals. See A/C RELAY TEST table. See Fig. 2 . 
Replace relay if continuity is not as specified. 

A/C RELAY TEST 

Terminal

Continuity

"D" & "A"

(1)

 Yes

"F" & "A"

(1)

 Yes

(1)

Continuity exists in only one direction.

Test Between Terminals

Continuity

"A" & "B"

(1)

 Yes

"C" & "D"

(1)

 No

"C" & "D"

(2)

 Yes

(1)

With no voltage applied.

(2)

With battery voltage applied to terminals "A" and "B".

 

1997 Mazda MX-5 Miata 

A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System

  

Fig. 2: Identifying A/C Relay Terminals 
Courtesy of MAZDA MOTORS CORP. 

CONDENSER FAN RELAY 

Remove condenser fan relay. Check continuity between indicated relay terminals. See CONDENSER FAN 
RELAY TEST table. See Fig. 3 . If continuity is not as specified, replace relay. 

CONDENSER FAN RELAY TEST 

Test Between Terminals

Continuity

"A" & "B"

(1)

 Yes

"C" & "E"

(1)

 No

"C" & "F"

(1)

 Yes

"C" & "E"

(2)

 Yes

(1)

With no voltage applied.

(2)

With battery voltage applied to terminals "A" and "B".

 

1997 Mazda MX-5 Miata 

A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System

  

Fig. 3: Identifying Condenser Fan Relay Terminals 
Courtesy of MAZDA MOTORS CORP. 

CONDENSER FAN MOTOR 

Disconnect condenser fan motor connector. Connect positive battery lead to condenser fan motor Black/Yellow 
wire terminal, and ground Black wire terminal. Replace condenser fan motor if it does not operate. 

EVAPORATOR THERMOSWITCH 

1. Remove glove box. Operate engine at idle. Turn A/C off. Turn blower switch to 4th position (high) for a 

few minutes to ensure evaporator temperature is greater than 32°F (0°C). Turn blower switch and engine 
off.  

2. Disconnect evaporator thermoswitch connector. Check continuity between thermoswitch terminals. If 

continuity exists, go to next step. If there is no continuity, replace thermoswitch.  

3. Submerge thermoswitch sensing bulb in ice cold water of less than 32°F (0°C). Ensure continuity does 

not exist between thermoswitch terminals. Replace thermoswitch if continuity is not as specified.  

PRESSURE SWITCH 

1. Turn ignition off. Connect manifold pressure gauge set to system. If high-side pressure is 37-310 psi (2.6-

22.0 kg/cm

2

 ), go to next step. If pressure is not as specified, check refrigerant level.  

2. Disconnect pressure switch connector. Check continuity between switch terminals. If continuity exists, 

pressure switch is okay. If there is no continuity, replace pressure switch.  

REMOVAL & INSTALLATION 

 

1997 Mazda MX-5 Miata 

A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System

  

COMPRESSOR 

Removal & Installation 

1. Before disconnecting negative battery cable, obtain radio anti-theft code from vehicle owner. Disconnect 

negative battery cable.  

2. Raise and support front of vehicle with safety stands. Discharge A/C system using approved refrigerant 

recovery/recycling equipment. Remove splash shield and air guide.  

3. Disconnect compressor clutch connector. Disconnect refrigerant lines from compressor, and plug open 

fittings. Remove compressor drive belt. Remove compressor bolts and compressor. To install, reverse 
removal procedure. Adjust drive belt deflection. Apply clean compressor oil to "O" ring before 
connecting fittings. DO NOT apply compressor oil to fitting nuts. Evacuate and charge A/C system. 
Check for leaks.  

CONDENSER & RECEIVER-DRIER 

Removal 

Raise and support front of vehicle with safety stands. Discharge A/C system using approved refrigerant 
recovery/recycling equipment. Remove splash shield and air guide. Remove condenser. Remove receiver-drier. 
Plug open fittings. 

Installation 

To install, reverse removal procedure. Apply clean compressor oil to "O" rings before connecting fittings. DO 
NOT apply compressor oil to fitting nuts. If installing new condenser, add 1.0 ounce of compressor oil to A/C 
compressor. If installing new receiver-drier, add .3 ounce of compressor oil to A/C compressor. Evacuate and 
charge A/C system. Check for leaks. 

EVAPORATOR UNIT 

Removal 

1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect refrigerant 

pipes from evaporator tubes at engine compartment firewall and plug open fittings. Remove passenger-
side instrument panel undercover. Remove glove box.  

2. Disconnect electrical connectors. Loosen seal plates between evaporator unit, heater unit and blower unit. 

Remove evaporator unit. Disassemble evaporator unit to remove evaporator core and thermo-switch. See 

WARNING:

To avoid injury from accidental air bag deployment, read and follow all 
SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG 
SYSTEM procedures in AIR BAG RESTRAINT SYSTEM article in the 
ACCESSORIES/SAFETY EQUIPMENT section.

NOTE:

For removal and installation procedures not covered in this article, see HEATER 
SYSTEM article.

 

1997 Mazda MX-5 Miata 

A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System