1991 MAZDA MIATA fan switch

CONTROL UNITS LOCATION
SENDING UNITS & SENSORS
SENDING UNITS & SENSORS LOCATION
MOTORS
MOTORS LOCATION
SOLENOIDS & SOLENOID VALVES
SOLENOIDS & SOLENOID VALVES LOCATION
ComponentLocation
ABS Control UnitBehind center of dash, near ECU.
Cruise Control UnitBehind left side of dash, above fuse block.
Engine Control Unit (ECU)Behind center of dash. See Fig. 2 .
Supplemental Safety Restraint (SRS)
ModuleBehind left side of dash. See Fig. 3 .
ComponentLocation
ABS Wheel SensorsOn each front & rear wheel hub
assembly.
Airflow MeterConnected to air filter housing. See Fig.
2 .
Atmospheric Pressure SensorBuilt-in ECU.
Brake Fluid Level SensorInside brake master cylinder.
Coolant Temperature SensorOn water outlet, at left rear of engine. See
Fig. 2
.
Cooling Fan ThermoswitchOn thermostat housing.
Crank Angle SensorOn right rear side of cylinder head. See
Fig. 2
.
Intake Air ThermosensorIn airflow sensor unit.
Oil Pressure SensorOn left side of engine near oil filter.
SRS Crash/Impact Sensors
FrontOn center, left and right front of
vehicle. See Fig. 3
.
CenterBehind center of dash. See Fig. 3 .
Throttle Position Sensor (TPS)Mounted on side of throttle body. See
Fig. 2
.
ComponentLocation
A/C-Heater Blower MotorBehind left side of dash.
Wiper MotorOn right side of firewall.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
Microsoft
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Any modification to the exhaust system on turbo models, which reduces exhaust backpressure, will lead to lean
fuel mixtures and excessive spark advance. This could cause serious engine damage.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
ENGINE OIL
FUEL SYSTEM SERVICE
HALOGEN BULBS
Halogen bulbs contain pressurized gas which may explode if overheated. DO NOT touch glass portion of bulb
with bare hands. Eye protection should be worn when handling or working around halogen bulbs.
HEADLIGHT RETRACTOR
RADIATOR CAP
RADIATOR FAN WARNING:Many solid state electrical components can be damaged by static
electricity (ESD). Some will display a warning label, but many will not.
Discharge personal static electricity by touching a metal ground point on
the vehicle prior to servicing any ESD sensitive component.
CAUTION: Never use non-detergent or straight mineral oil.
WARNING:Relieve fuel system pressure prior to servicing any fuel system
component (fuel injection models).
CAUTION: If headlight retractor freezes during cold weather operation, DO NOT
attempt to force mechanism. Headlights should be kept raised at all times
in cold weather. To raise them, use only headlight retractor switch. DO
NOT use headlight switch.
CAUTION: Always disconnect the fan motor when working near the radiator fan. The
fan is temperature controlled and could start at any time even when the
ignition key is in the OFF position. DO NOT loosen or remove radiator cap
when cooling system is hot.
WARNING:Keep hands away from radiator fan. Fan is controlled by a thermostatic
switch which may come on or run for up to 15 minutes even after engine
is turned off.

1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda
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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
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
Microsoft
Sunday, July 05, 2009 2:11:52 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 2:11:52 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 2:11:52 PMPage 6 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
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