MAZDA MX-5 1997 Factory Repair Manual

ELECTRICAL COMPONENT LOCATIONS
OPERATION
All air control doors are controlled manually by cable from control panel. Blower resistor determines blower
speed. With blower switch in high position, blower motor is grounded directly through blower switch. With
blower switch in all other positions, blower motor is grounded through blower resistor and blower switch.
A/C compressor clutch circuit is completed when A/C relay is energized and pressure switch is closed. A/C
relay is energized when Powertrain Control Module (PCM) grounds the solenoid circuit of the relay. The PCM
energizes A/C relay if evaporator thermoswitch is closed and A/C and blower switches are on. The PCM also
controls A/C relay operation according to engine load.
ADJUSTMENTS
TESTING
A/C SYSTEM PERFORMANCE
1. Connect manifold gauge set. Operate engine at 1500 RPM. Operate A/C at maximum cooling, recirculate,
fan on high, vent mode. Close all doors and windows. Place thermometer at center vent outlet.
2. Allow A/C to stabilize. Ensure high pressure is 200-227 psi (14.0-16.0 kg/cm
2 ). Read temperature at
center vent outlet. Ensure temperature is within 39-43°F (3-6°C)
A/C COMPRESSOR CLUTCH CIRCUIT
ComponentLocation
A/C RelayRight Front Corner Of Engine Compartment
Condenser FanRight Front Corner Of Engine Compartment
Blower ResistorBottom Of Blower Case
Evaporator ThermoswitchOn Evaporator Upper Case
Pressure SwitchIn High-Pressure Line, Between Receiver-Drier &
Evaporator
NOTE: For door control cable adjustments, see ADJUSTMENTS in HEATER SYSTEM

article.
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 test procedures not covered in this article, see TESTING in HEATER
SYSTEM article.

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
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1. Check WIPER fuse (20-amp) in passenger compartment fuse block. Check AD FAN (additional fan) fuse
(20-amp) in engine compartment fuse block. If fuses are okay, go to next step. If either fuse is blown,
check for shorted wiring harness before replacing fuse.
2. Operate engine at idle. Turn A/C and blower on. Using voltmeter, backprobe Black/Red wire terminal of
compressor clutch connector. If battery voltage exists, replace compressor clutch. If battery voltage is not
present, go to next step.
3. Ensure engine is running. Ensure A/C and blower are on. Using a voltmeter, backprobe Blue/Yellow wire
terminal of the A/C relay connector. If battery voltage exists, go to next step. If battery voltage does not
exist, repair open Blue/Yellow wire between AD FAN fuse and A/C relay.
4. Backprobe Blue wire terminal of A/C relay connector. If battery voltage exists, go to next step. If battery
voltage is not present, repair open Blue wire between WIPER fuse and A/C relay.
5. Backprobe Black/Red wire terminal of A/C relay connector. If battery voltage exists, repair open
Black/Red wire between A/C relay and compressor clutch. If battery voltage is not present, go to next
step.
6. Backprobe Blue/Black wire terminal of A/C relay connector. If voltage is Zero volts, replace A/C relay. I
f
voltage is not Zero volts, repair open Blue/Black wire between A/C relay and PCM. If wire is okay, check
PCM operation.
CONDENSER (ADDITIONAL) FAN CIRCUIT
1. Check ENGINE fuse (30-amp) in passenger compartment fuse block. Check AD FAN fuse (20-amp) in
engine compartment fuse block. If fuses are okay, go to next step. If either fuse is blown, check for
shorted wiring harness before replacing fuse.
2. Start engine. Turn A/C and blower switches on. Using voltmeter, backprobe Black/Yellow wire terminal
of condenser fan motor. If battery voltage exists, go to next step. If battery voltage is not present, go to
step 4).
3. Turn ignition switch off. Disconnect condenser fan connector. Using ohmmeter, check continuity
between Black wire of condenser fan connector and ground. If continuity exists, replace condenser fan. If
continuity is not present, repair open Black wire between condenser fan and ground.
4. Turn ignition on. Ensure A/C and blower switches are on. Using voltmeter, backprobe Black/White wire
terminal of condenser fan relay connector. If battery voltage exists, go to next step. If battery voltage is
not present, repair open Black/White wire between ENGINE fuse and condenser fan relay.
5. Backprobe Blue/Yellow wire terminal of condenser fan relay connector. If battery voltage exists, go to
next step. If battery voltage is not present, repair open Blue/Yellow wire between AD FAN fuse and
condenser fan relay.
6. Backprobe Black/Yellow wire terminal of condenser fan relay connector. If battery voltage exists, repair
open Black/Yellow wire between condenser fan relay and condenser fan. If battery voltage is not present,
go to next step.
7. Backprobe Blue/White wire terminal of condenser fan relay connector. If battery voltage exists, repair
Blue/White wire between condenser fan relay and PCM. If wire is okay, check PCM operation. If battery
voltage is not present, replace condenser fan relay.
A/C SWITCH

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
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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
TerminalContinuity
"D" & "A"(1) Yes
"F" & "A"(1) Yes
(1)Continuity exists in only one direction.
Test Between TerminalsContinuity
"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
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

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 TerminalsContinuity
"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
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
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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
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 7 © 2005 Mitchell Repair Information Company, LLC.

Fig. 4 .
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 evaporator, add 1.7 ounces of compressor oil to A/C
compressor. Evacuate and charge A/C system. Check for leaks.
Fig. 4: Exploded View Of Evaporator Unit

Courtesy of MAZDA MOTORS CORP.
TORQUE SPECIFICATIONS

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 8 © 2005 Mitchell Repair Information Company, LLC.

TORQUE SPECIFICATIONS
WIRING DIAGRAM
ApplicationFt. Lbs. (N.m)
Compressor Bracket-To-Engine Bolt28-38 (38-51)
Compressor-To-Compressor Bracket Bolt11-15 (15-21)
Refrigerant Pipe Fittings
Condenser Inlet11-18 (15-24)
Evaporator Outlet15-21 (20-29)
INCH Lbs. (N.m)
Evaporator Unit Nut71-97 (8-11)
Refrigerant Pipe Fittings
Compressor Inlet & Outlet89-132 (10-15)
Evaporator Inlet89-168 (10-19)
Receiver-Drier Inlet & Outlet89-168 (10-19)
Steering Wheel Nut79-121 (9-14)

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 9 © 2005 Mitchell Repair Information Company, LLC.

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 10 © 2005 Mitchell Repair Information Company, LLC.

Fig. 5: Manual A/C-Heater System Wiring Diagram

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
Sunday, July 05, 2009 1:41:48 PMPage 11 © 2005 Mitchell Repair Information Company, LLC.