battery MAZDA MIATA 1991 Factory Owner's Manual

wire terminal of blower resistor 4-wire connector. If no voltage is present, replace blower resistor.
5. If battery voltage is present, check voltage at Blue/Green wire terminal of blower resistor connector. If no
voltage is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Yellow wire
terminal of blower resistor connector.
6. If no voltage is present, replace blower resistor. If battery voltage is present, turn ignition on and blower
switch to 4th position (high). Check voltage at Black wire terminal of blower switch connector. If battery
voltage is present, repair wiring between blower switch and ground.
7. If no voltage is present, turn ignition switch, blower switch and A/C switch off. Check voltage at
Blue/White wire terminal of blower switch connector. If no voltage is present, repair wiring between
blower resistor and blower switch.
8. If battery voltage is present, check voltage at Blue/Red wire terminal of blower switch connector. If no
voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is present,
check voltage at Blue/Green wire terminal of blower switch connector.
9. If no voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is
present, check voltage at Blue/Yellow wire terminal of blower switch connector. If battery voltage is
present, replace blower switch. If no voltage is present, repair wiring between blower resistor and blower
switch.
BLOWER MOTOR
Disconnect 2-wire connector from bottom of blower motor case. Apply battery voltage across terminals.
Replace blower motor if it does not operate.
BLOWER SWITCH
With blower switch in positions indicated, check continuity between specified terminals of blower switch
connector. See Fig. 2
. If continuity is not as specified, replace blower switch.

1991 Mazda MX-5 Miata
HEATER SYSTEM 1990-92 Heater Systems
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Drain coolant. Disconnect heater hoses at engine compartment firewall. Remove grommets from holes (if
equipped). Remove instrument panel. Remove heater case. Disassemble case and remove heater core. See Fig.
1 . To install, reverse removal procedure. Fill cooling system.
INSTRUMENT PANEL
Removal & Installation
Obtain code number and deactivate audio anti-theft system. Disconnect negative battery cable. Remove all
components in 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

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HEATER SYSTEM 1990-92 Heater Systems
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3. If battery voltage is present, turn off blower switch and A/C switch (if equipped). Check voltage at
Blue/Red wire terminal of blower resistor 1-wire connector. If no voltage is present, replace blower
motor. If battery voltage is present, check voltage at Blue/White wire terminal of blower resistor
connector.
4. If no voltage is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Red
wire terminal of blower resistor 4-wire connector. If no voltage is present, replace blower resistor.
5. If battery voltage is present, check voltage at Blue/Green wire terminal of blower resistor connector. If no
voltage is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Yellow wire
terminal of blower resistor connector.
6. If no voltage is present, replace blower resistor. If battery voltage is present, turn ignition on and blower
switch to 4th position (high). Check voltage at Black wire terminal of blower switch connector. If battery
voltage is present, repair wiring between blower switch and ground.
7. If no voltage is present, turn ignition switch, blower switch and A/C switch off. Check voltage at
Blue/White wire terminal of blower switch connector. If no voltage is present, repair wiring between
blower resistor and blower switch.
8. If battery voltage is present, check voltage at Blue/Red wire terminal of blower switch connector. If no
voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is present,
check voltage at Blue/Green wire terminal of blower switch connector.
9. If no voltage is present, repair wiring between blower resistor and blower switch. If battery voltage is
present, check voltage at Blue/Yellow wire terminal of blower switch connector. If battery voltage is
present, replace blower switch. If no voltage is present, repair wiring between blower resistor and blower
switch.
COMPRESSOR CLUTCH CIRCUIT
1. Turn ignition on. Check 20-amp WIPER fuse in passenger compartment fuse block. Check 20-amp AD
FAN (additional fan) fuse in engine compartment fuse block. If fuses are blown, repair short circuit.
2. If fuses are okay, run engine at idle. Turn A/C and blower switches on. Check voltage at compressor
clutch connector (Black/Red wire terminal). If no voltage is present, go to step 5).
3. If battery voltage is present, turn ignition off. Disconnect evaporator thermoswitch connector. Check
continuity between switch terminals. If there is no continuity, replace evaporator thermoswitch.
4. If there is continuity, disconnect compressor clutch connector. Set ohmmeter to X1000 scale. Check
continuity between compressor clutch connector and ground. If there is no continuity, replace compressor
clutch. If there is continuity, adjust compressor clutch air gap or check compressor for internal damage.
5. Run engine at idle. Turn A/C and blower switches on. Check voltage at Black/Blue wire terminal of A/C
relay connector. If battery voltage is present, go to step 9).
6. If no voltage is present, check voltage at Blue/Yellow wire terminal of A/C relay connector. If no voltage
is present, repair circuit between 20-amp AD FAN fuse and A/C relay.
7. If battery voltage is present, check voltage at Blue wire terminal of A/C relay connector. If no voltage is
present, repair circuit between 20-amp WIPER fuse and A/C rela
y. NOTE: Blower resistor uses a 1-wire connector and a 4-wire connector. The wire
in the 1-wire connector is Blue/Red, and one of the wires in the 4-wire
connector is Blue/Red. Check voltage at appropriate wire.

1991 Mazda MX-5 Miata
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8. If battery voltage is present, check voltage at Blue/Black wire terminal of A/C relay connector. If no
voltage is present, replace A/C relay. If battery voltage is present, check Engine Control Unit (ECU)
terminal voltage.
9. Turn ignition off. Disconnect pressure switch connector. Check continuity between switch terminals. If
there is continuity, repair circuit between A/C relay and compressor clutch.
10. If there is no continuity, connect manifold pressure gauges to system. If low pressure is 21-43 psi (1.5-3.0
kg/cm
2 ) and high pressure is 171-235 psi (12.0-16.5 kg/cm2 ), replace pressure switch. If pressures are
not as specified, check refrigerant system for proper charge.
CONDENSER (ADDITIONAL) FAN CIRCUIT
1. Turn ignition on. Turn A/C and blower switches on. Check voltage at Black/Blue wire terminal of
condenser fan connector. If no voltage is present, repair circuit between A/C relay and condenser fan.
2. If battery voltage is present, check voltage at Black wire terminal of condenser fan connector. If no
voltage is present, replace condenser fan motor. If battery voltage is present, repair circuit between
condenser fan and ground.
A/C & BLOWER SWITCH
With switches in positions indicated, check continuity between specified terminals of A/C and blower switch
connector. See Fig. 1
. If continuity is not as specified, replace A/C and blower switch.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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Fig. 1: Testing A/C & Blower Switch
Courtesy of MAZDA MOTORS CORP.
A/C RELAY
1. Remove relay. Check continuity between specified terminals of relay connector. See A/C RELAY TEST
table. See Fig. 2 . Ensure test lead polarity is correct. If continuity is not as specified, replace relay.
2. If continuity is as specified, apply battery positive lead to terminal "D" and negative lead to terminal "A".
Check continuity between terminals "E" and "C". If there is continuity, relay is okay. If there is no
continuity, replace relay.
A/C RELAY TEST
Fig. 2: A/C Relay Connector Terminal ID

Courtesy of MAZDA MOTORS CORP.
Terminal (+)(1) Terminal (-)(2) Continuity
ABYes
ADYes
BANo
CENo
DANo
ECYes
(1)Connect ohmmeter positive lead to this terminal.
(2)Connect ohmmeter negative lead to this terminal.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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BLOWER MOTOR
Disconnect 2-wire connector from bottom of blower motor case. Apply battery voltage across blower motor
terminals. Replace blower motor if it does not operate.
BLOWER RESISTOR
Note 4-wire connector and 1-wire connector attached to seam where upper and lower blower cases meet. Wires
in these connectors lead to blower resistor on bottom of blower case. Disconnect both connectors. If continuity
does not exist between 1-wire connector terminal and each terminal of 4-wire connector, replace blower
resistor.
CONDENSER (ADDITIONAL) FAN MOTOR
Disconnect condenser fan connector. Apply battery voltage across condenser fan terminals. Replace condenser
fan motor if it does not operate.
EVAPORATOR THERMOSWITCH
1. Remove glove box. Run engine at idle. Turn off A/C switch. Turn blower switch to 4th position (high) for
a few minutes to ensure evaporator temperature is greater than 32°F (0°C). Turn off blower switch and
engine.
2. Disconnect evaporator thermoswitch connector. Check continuity between switch terminals. If there is
continuity, thermoswitch is okay. If there is no continuity, replace thermoswitch.
PRESSURE SWITCH
1. Turn ignition off. Connect manifold pressure gauges to system. If high-side pressure is less than 31.2 psi
(2.2 kg/cm
2 ), check system for proper refrigerant charge.
2. If high-side pressure is greater than 31.2 psi (2.2 kg/cm
2 ), disconnect pressure switch connector. Check
continuity between switch terminals. If there is continuity, switch is okay. If there is no continuity,
replace switch.
REMOVAL & INSTALLATION
AIR BAG WARNING
BLOWER CASE
Removal & Installation
WARNING:To avoid injury from accidental air bag deployment, read and carefully
follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR
BAG SYSTEM procedures in AIR BAG article in the
ACCESSORIES/SAFETY EQUIPMENT Section.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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Disconnect electrical connectors from blower case. Remove glove box. Loosen seal plate between blower motor
case and evaporator case. Remove blower motor case nuts. Remove case and seal plate. To install, reverse
removal procedure.
COMPRESSOR
Removal & Installation
1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling
equipment. Disconnect compressor clutch connector. Disconnect refrigerant lines from compressor.
Remove drive belt.
2. Raise and support vehicle. Remove compressor mounting bolts and remove compressor. To install,
reverse removal procedure. Adjust drive belt to specified tension. Evacuate and charge system.
CONDENSER & RECEIVER-DRIER
Removal & Installation
Discharge A/C system using approved refrigerant recovery/recycling equipment. Raise and support vehicle.
Remove splash shield and air guide. Remove condenser and receiver-drier as an assembly. To install, reverse
removal procedure. Evacuate and charge system.
CONTROL PANEL
Removal & Installation
Remove rear console assembly. See Fig. 4 . Remove vent outlets from center panel assembly. Remove center
panel assembly. Remove control panel screws. Pull control panel from hole. Disconnect door control cables
from back of control panel and remove panel. To install, reverse removal procedure.
EVAPORATOR CORE & THERMOSWITCH
Removal & Installation
1. Discharge A/C system using approved refrigerant recovery/recycling equipment. Remove condenser and
receiver-drier as an assembly. Disconnect low-pressure and high-pressure pipes from evaporator tubes at
engine compartment firewall.
2. Remove right undercover and glove box. Disconnect thermoswitch electrical connector. Loosen left seal
plate (between heater case and evaporator case). Loosen right seal plate (between evaporator case and
blower motor case).
3. Remove evaporator case. Disassemble evaporator case, and remove evaporator core and thermoswitch.
See Fig. 3
. To install, reverse removal procedure. Evacuate and charge system.

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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Sunday, July 05, 2009 2:11:52 PMPage 7 © 2005 Mitchell Repair Information Company, LLC.

Removal & Installation
Obtain code number and deactivate audio anti-theft system. Disconnect negative battery cable. Remove all
components in order listed in illustration. See Fig. 4
. To install, reverse removal procedure.
Fig. 4: Exploded View of Instrument Panel

Courtesy of MAZDA MOTORS CORP.
WIRING DIAGRAMS

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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REMOVAL & INSTALLATION
STEERING GEAR
Removal & Installation (Miata & MPV)
1. Disconnect negative battery cable. Raise and support front of vehicle. Remove front wheels. Remove
cotter pins and castle nuts from tie rod ends.
2. Using puller, remove tie rods from steering knuckles. Remove steering column intermediate shaft-to-
steering gear pinion shaft bolt. Mark reference lines on pressure pipe fittings.
3. Remove pressure and return hose connections from steering gear. Remove 2 steering bracket-to-frame
mounting through bolts. Remove steering gear and linkage with steering bracket attached from under the
vehicle.
4. To install, reverse removal procedure. Fill and bleed system. Tighten bolts to specification. See
TORQUE SPECIFICATIONS
table. Tighten steering gear-to-mounting bracket bolts (4) in the
following order: left front, right front, left rear, right rear.
Removal & Installation (MX-6 & 626)
1. Disconnect negative battery cable and power steering pressure switch connectors. Raise and support front
of vehicle. Remove front wheels.
2. Remove cotter pins and castle nuts from tie rod ends. Using puller, remove tie rods from steering
knuckles. Remove steerin
g column intermediate shaft-to-steering gear pinion shaft bolt.
Used Belt.35-.39 (8.9-10.0)
MPV
V6
New Belt.28-.30 (7.1-7.6)
Used Belt.30-.32 (7.6-8.1)
4-Cylinder
New Belt.26-.28 (6.6-7.1)
Used Belt.28-.31 (7.1-7.8)
MX-6 & 626
New Belt.31-.36 (7.8-9.1)
Used Belt.35-.43 (8.9-10.9)
RX7
New Belt.43-.51 (10.9-12.9)
Used Belt.55-.63 (14.0-16.0)
929
New Belt.28-.35 (7.1-8.9)
Used Belt.35-.43 (8.9-10.9)
(1)Belt deflection is measured at midpoint between idler pulley and pump, with 22 lbs. (10 kg.) of
pressure applied.

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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3. Remove pressure and return hose connections from steering gear. Remove mud flap on driver's side.
Remove steering gear mounting bolts. Remove steering gear through wheelwell on driver's side.
4. To install, reverse removal procedure. Fill and bleed system. Tighten bolts to specification. See
TORQUE SPECIFICATIONS
table.
Removal & Installation (Protege & 323)
1. Disconnect negative battery cable. Raise and support front of vehicle. Remove front wheels. Remove
engine undercover. Remove cotter pins and castle nuts from tie rod ends.
2. Using puller, remove tie rods from steering knuckles. Remove steering column intermediate shaft-to-
steering gear pinion shaft bolt. Remove pressure and return hose connections from steering gear box.
3. Remove all accessible steering gear mounting bracket upper nuts and lower bolts. On Protege, support
drive train from above. Loosen stabilizer bar left mounting bracket and remove engine mount
crossmember.
4. Remove transmission control cable clip. Remove transfer case mount nuts. Lower engine gradually until
rear engine mount bolts can be removed. Remove lower left steering gear mounting bolt from between
transaxle and transfer case.
5. On all models, remove steering gear. To install, reverse removal procedure. Fill and bleed system.
Tighten bolts to specification. See TORQUE SPECIFICATIONS
table.
Removal & Installation (RX7)
1. Remove battery. Drain cooling system. Remove fan shroud and radiator. Raise and support front of
vehicle. Remove front wheels and engine undercover.
2. Remove control links and stabilizer bar. Remove cotter pins and castle nuts from tie rod ends. Remove tie
rods from steering knuckles with puller.
3. Remove steering column intermediate shaft-to-steering gear pinion shaft bolt. Remove pressure and
return hose connections from steering gear box.
4. Remove steering gear mounting bolts. Lower steering gear brackets, steering gear and linkage from
vehicle as an assembly.
5. To install, reverse removal procedure. Fill and bleed system. Tighten bolts to specification. See
TORQUE SPECIFICATIONS
table.
Removal & Installation (929)
1. Disconnect negative battery cable. Raise and support front of vehicle. Remove front wheels. Remove
engine undercover. Disconnect pressure and return hose connections in front of steering gear.
2. Drain fluid. Disconnect return hose fitting to control valve. Remove starter for access to control valve.
Disconnect control valve and pressure switch connectors. Remove control valve. Remove cotter pins and
castle nuts from tie rod ends.
3. Using puller, remove tie rods from steering knuckles. Remove steering column intermediate shaft-to-
steering gear pinion shaft bolt. Remove steering gear mounting bolts. Remove steering gear from bottom
of vehicle.
4. To install, reverse removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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