1991 MAZDA MIATA service

1. Disconnect hydraulic unit 12-pin connector. Using a DVOM, measure resistance between Green/Black
and Yellow/Red wires, Green/White and Yellow/Red wires and Yellow and Yellow/Red wires.
Resistance should be 1-1.2 ohms in each measurement.
2. If resistance if not as specified, replace hydraulic unit. If resistance is as specified, check wiring harness
between ABS control unit and hydraulic unit.
HYDRAULIC UNIT
Only serviceable parts of hydraulic unit are motor relay and valve relay. If other parts of unit malfunction,
replace hydraulic unit assembly.
MOTOR RELAY
Continuity Tests
1. Disconnect negative battery cable. Remove motor relay from hydraulic unit. Ensure continuity exists
between terminals "B" and "C" of motor relay. See Fig. 11
. Connect 12 volts to terminal "C", and ground
terminal "B". Ensure continuity exists between terminals "A" and "D".
2. Replace relay if continuity is not as specified. If continuity is as specified, check wiring harness between
motor relay and ABS control unit fuse (60 amps).
Fig. 11: Identifying Motor & Valve Relay Terminals

Courtesy of MAZDA MOTORS CORP.
PUMP MOTOR
Continuity Test (Miata)

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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Fig. 1: Adjusting Brake Booster Push Rod (Navajo)
Courtesy of FORD MOTOR CO.
2. Place gauge against master cylinder mounting surface of booster. Adjust push rod screw by turning it
until end of screw just touches inner edge of gauge slot.
REAR BRAKE SHOES
B2200 & B2600i 2WD
NOTE: Self-adjusting rear brakes only require manual adjustment when brake shoe is
replaced or operating lever is moved during service operations.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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engagement while rotating adjusting screw to prevent burring screw slots. Ensure adjusting screw rotates
freely.
PARKING BRAKE
B2200 & B2600i
1. Depress brake pedal several times while vehicle is moving in Reverse. Ensure brakes are properly
adjusted. Pull parking brake lever with a force of 44 lbs. (20 kg). If stroke is 7-12 notches, parking brake
is properly adjusted.
2. If stroke is not 7-12 notches, raise and support rear of vehicle. Release parking brake lever. Loosen cable
lock nut at lever end of cable. Rotate adjusting nut until correct stroke is obtained. Operate parking brake
several times and ensure rear wheels rotate freely. Ensure parking brake warning light illuminates when
brake lever is pulled one notch.
Navajo
1. Adjust service brakes before adjusting parking brake cable. Ensure brake drums are cold. Apply parking
brake to fully depressed position. Grip threaded rod to prevent it from spinning.
2. Thread equalizer nut 6 full turns past its original position on threaded rod. See Fig. 4
. Check cable
tension at rear of equalizer assembly using Cable Tension Gauge (021-00018). If tension is not 400-600
lbs. (182-272 k
g), repeat step 2).

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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2. Release parking brake lever. Using a screwdriver, reach through parking brake handle hole in console and
rotate adjusting screw until stroke is 6-8 notches. Ensure rear wheels rotate freely. Ensure parking brake
warning light illuminates when brake lever is pulled one notch.
Miata, MX-6, MPV, Protege, RX7, 323, 626
1. On models with rear disc brakes, depress brake pedal several times. On models with rear drum brakes,
start engine and depress brake pedal several times while vehicle is moving in Reverse. Stop engine.
2. On all models, pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 5-7 notches, parking
brake is properly adjusted. If stroke is not 5-7 notches, raise and support rear of vehicle. Release parking
brake lever.
3. Rotate cable adjusting nut at lever end of cable (under console cover) until stroke is within specification.
On models equipped with rear disc brakes, ensure clearance between stopper and lever (at each caliper) is
not less than .08" (2 mm) on RX7, or zero on all other models. On all models, ensure parking brake
warning light illuminates when brake lever is pulled one notch.
PARKING BRAKE SHOES
929
Raise and support vehicle. Remove rear wheels. Remove service plug from rotor. Using a screwdriver, rotate
star wheel adjuster toward axle until rotor locks. Rotate adjuster in opposite direction 3-5 notches. Ensure rotors
turn freely and parking brake functions properly. Install service plug and rear wheels.
PEDAL FREE PLAY
Depress pedal a few times to eliminate vacuum. Pedal free play should be .16-.28" (4-7 mm). Adjust play by
loosening push rod lock nut. Turn push rod until correct free play is obtained. Tighten push rod lock nut.
PEDAL HEIGHT & STOPLIGHT SWITCH
1. Released pedal height is measured from carpet surface on vertical portion of firewall to pedal pad center.
Disconnect stoplight switch electrical connector. Loosen lock nut on stoplight switch. Move switch away
from pedal. Loosen push rod lock nut. Turn rod until correct pedal height is obtained. See BRAKE
PEDAL HEIGHT SPECIFICATIONS .
2. Adjust pedal free play. See PEDAL FREE PLAY
under ADJUSTMENTS. Tighten push rod lock nut.
Rotate stoplight switch until it contacts pedal and then rotate an additional 1/2 turn. Tighten stoplight
switch lock nut. Reconnect stoplight switch electrical connector.
3. Applied pedal height is measured from angled portion of firewall (without carpet) to pedal pad center.
Start engine. On B2200, B2600i and MPV, depress brake pedal with 33 lbs. (15 kg) pressure. On all other
models, depress brake pedal with 132 lbs. (60 k
g) pressure. tension should be checked and adjusted.
NOTE: Pedal height and stoplight switch information is not available for Navajo.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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23 - Empty
24 - 10 Amp (Red) Interior Lights, Warning Buzzers, Radio/Cassette, Compact Disc Player, Clock
25 - 15 Amp (Blue) Radio/Cassette, Compact Disc Player, Clock, Cigarette Lighter
26 - Empty
27 - Empty
BATTERY SPECIFICATIONS
Vehicle is equipped with a special 9 9/16" x 4 3/4" x 7 3/8" 12-volt battery that is vented to outside of vehicle.
CAUTIONS & WARNINGS
SUPPLEMENTAL RESTRAINT SYSTEM (AIR BAG)
Modifications or improper maintenance, including incorrect removal and installation of the Supplemental
Restraint System (SRS), can adversely affect system performance. DO NOT cover, obstruct or change the
steering wheel horn pad in any way, as such action could cause improper function of the system. Use only plain
water when cleaning the horn pad. Solvents or cleaners could adversely affect the air bag cover and cause
improper deployment of the system.
AIR CONDITIONING SERVICING CAUTION: When battery is disconnected, vehicles equipped with computers may
lose memory data. When battery power is restored, driveability problems
may exist on some vehicles. These vehicles may require a relearn
procedure. See COMPUTER RELEARN PROCEDURES article in the
GENERAL INFORMATION Section.
NOTE: See the AIR BAGS article in the ACCESSORIES/SAFETY EQUIPMENT Section.
WARNING:To avoid injury from accidental air bag deployment, read and carefully
follow all warnings and service precautions. See appropriate AIR BAGS
article in ACCESSORIES/SAFETY EQUIPMENT.
CAUTION: Disconnect negative battery cable before servicing any air bag system,
steering column or passenger side dash component. After any repair, turn
ignition key to the ON position from passenger's side of vehicle in case of
accidental air bag inflation
CAUTION: Avoid breathing R-134a refrigerant and PAG lubricant vapors, exposure
may irritate eyes, nose and throat. To remove R-134a from system use R-
134a recycling equipment that meets SAE J2210 specifications. If
accidental system discharge occurs, ventilate work area before resuming

1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda
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ANTI-LOCK BRAKE SYSTEM
The anti-lock brake system contains electronic equipment that can be susceptible to interference caused by
improperly installed or high output radio transmitting equipment. Since this interference could cause the
possible loss of the anti-lock braking capability, such equipment should be installed by qualified professionals.
On models equipped with anti-lock brake systems, ALWAYS observe the following cautions:
DO NOT attempt to bleed hydraulic system without first referring to the appropriate ANTI-LOCK
BRAKE SYSTEM article in the BRAKES Section.
DO NOT mix tire sizes. As long as tires remain close to the original diameter, increasing the width is
acceptable. Rolling diameter must be identical for all 4 tires. Some manufacturers recommend tires of the
same brand, style and type. Failure to follow this precaution may cause inaccurate wheel speed readings.
Use ONLY recommended brake fluids. DO NOT use silicone brake fluids in an ABS-equipped vehicle.
BATTERY WARNING
REPLACING BLOWN FUSES
Before replacing a blown fuse, remove ignition key, turn off all lights and accessories to avoid damaging the
electrical system. Be sure to use fuse with the correct indicated amperage rating. The use of an incorrect
amperage rating fuse may result in a dangerous electrical system overload.
BRAKE PAD WEAR INDICATOR
Indicator will cause a squealing or scraping noise, warning that brake pads need replacement.
CATALYTIC CONVERTER
Continued operation of vehicle with a severe malfunction could cause converter to overheat, resulting in
possible damage to converter and vehicle. service.
WARNING:R-134a service equipment or vehicle A/C systems SHOULD NOT be
pressure tested or leak tested with compressed air. Some mixtures of
air/R134a have shown to be combustible at elevated pressures. These
mixtures are dangerous and may cause fire and/or explosions. See AIR
CONDITIONING SERVICE article in GENERAL INFORMATION section.
WARNING:When battery is disconnected, vehicles equipped with computers may
lose memory data. When battery power is restored, driveability problems
may exist on some vehicles. These vehicles may require a relearn
procedure. See COMPUTER RELEARN PROCEDURES article in GENERAL
INFORMATION section.

1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda
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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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HEATER SYSTEM
1990-92 Heater Systems
DESCRIPTION & OPERATION
Heater case, mounted under center of instrument panel, contains airflow mode door and air-mix (temperature
blend) door. See Fig. 1
. Blower case, mounted under right end of instrument panel, contains recirculated/fresh
air door. All doors are controlled manually from control panel by cable.
Blower motor relay, in left rear corner of engine compartment (on relay cluster), supplies power to blower
motor. Blower resistors, on bottom of blower case, determine blower speed.
Fig. 1: Exploded View of Heater Case

Courtesy of MAZDA MOTORS CORP. 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
HEATER SYSTEM 1990-92 Heater Systems

1991 Mazda MX-5 Miata
HEATER SYSTEM 1990-92 Heater Systems
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