1997 MAZDA MX-5 Factory Repair Manual

6. Turn ignition blower switch off. Backprobe Blue/White wire terminal, Blue/Red wire terminal,
Blue/Green wire terminal and Blue/Yellow wire terminal of blower switch connector If battery voltage is
not present, repair open wire(s) between blower resistor and blower switch. If battery voltage exists,
check blower motor.
BLOWER MOTOR
Disconnect blower motor 2-pin connector from bottom of blower case. Apply battery voltage across blower
motor terminals. Replace blower motor if it does not operate.
BLOWER RESISTOR
Disconnect blower resistor connectors from blower case. Check continuity, in turn, between Blue wire terminal
of 1-pin connector and each terminal of 4-pin connector. Ensure continuity exists. Replace resistor if continuity
does not exist.
BLOWER SWITCH
Disconnect blower switch connector. Place blower switch in indicated positions, and check continuity between
specified blower switch terminals. See BLOWER SWITCH TEST table. See Fig. 2
. If continuity is not as
specified, replace blower switch.
BLOWER SWITCH TEST
Switch PositionContinuity Between Terminals
Off(1)
Low"A" & "G"
Medium-Low"C", "G" & "H"
Medium-High"E", "G" & "H"
High"B", "G" & "H"
(1)There should not be continuity between any terminals.

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
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Fig. 2: Identifying Blower Switch Terminals
Courtesy of MAZDA MOTORS CORP.
REMOVAL & INSTALLATION
BLOWER UNIT
Removal & Installation
Remove glove box. Disconnect electrical connectors. Loosen seal plate between blower unit and evaporator unit
(if equipped). Remove blower unit bolts and blower unit. Disassemble blower unit to remove blower motor and
blower resistor. To install, reverse removal procedure.
CONTROL PANEL
Removal & Installation
Remove rear center console. Remove vent outlets from center panel. Remove center panel. Remove control
panel screws, and pull control panel from center panel. Disconnect heater control cables. To install, reverse
removal procedure.
HEATER CORE
Removal & Installation
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.

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
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Drain coolant. Disconnect heater hoses at engine compartment firewall. Remove grommets from holes (if
equipped). Remove instrument panel. See INSTRUMENT PANEL
. Remove heater unit. Disassemble heater
unit to remove heater core. See Fig. 1
. To install, reverse removal procedure. Fill cooling system.
INSTRUMENT PANEL
Removal & Installation
Before disconnecting negative battery cable, obtain radio anti-theft code from vehicle owner. Disconnect
negative battery cable. Remove components in the order listed in illustration. See Fig. 3
. To install, reverse
removal procedure.
Fig. 3: Exploded View Of Instrument Panel

Courtesy of MAZDA MOTORS CORP.
WIRING DIAGRAM

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
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1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
Microsoft
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Fig. 4: Heater System Wiring Diagram

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
Microsoft
Sunday, July 05, 2009 1:46:56 PMPage 7 © 2005 Mitchell Repair Information Company, LLC.

A/C-HEATER SYSTEM - MANUAL
1997 Manual A/C-Heater System
A/C SYSTEM SPECIFICATIONS
A/C SYSTEM SPECIFICATIONS
DESCRIPTION
Blower assembly, mounted under right side of instrument panel, contains blower motor, blower resistor and
fresh/recirculated air door. Evaporator unit, located left of blower case, contains evaporator, evaporator
thermoswitch and expansion valve. Heater unit, located left of evaporator case, contains heater core, airflow
mode door and air-mix (temperature blend) door.
ELECTRICAL COMPONENT LOCATIONS 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.
CAUTION: When battery is disconnected, radio will go into anti-theft protection
mode. Obtain radio anti-theft protection code from owner prior to
servicing vehicle.
ApplicationSpecifications
Compressor TypeNippondenso TV12 Rotary
Vane
Compressor Belt Deflection (1)
New5/16-23/64" (8-9 mm)
Used23/64-25/64" (9-10 mm)
Compressor Oil Capacity (2) 4.4-5.7 ozs.
Refrigerant Capacity21.2 ozs.
System Operating Pressures
High Side200-227 psi (14.0-16.0
kg/cm
2 )
Low Side22-35 psi (1.5-2.5
kg/cm
2 )
(1)Measure with 22-lb. (10 kg) pressure applied halfway between crankshaft pulley and Power Steering
(P/S) pulley or idler pulley (without P/S).
(2)Use ND-Oil 9 refrigerant oil.

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System

1997 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1997 Manual A/C-Heater System
Microsoft
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Microsoft
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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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