battery MAZDA MIATA 1991 Factory User Guide

DO NOT expose the ABS control unit to prolonged periods of high heat (185°F/85°C for 2 hours is
generally considered a maximum limit).
BLEEDING BRAKE SYSTEM
For ABS hydraulic unit bleeding, see HYDRAULIC UNIT under REMOVAL & INSTALLATION.
BRAKE LINE BLEEDING SEQUENCE
(1)
DIAGNOSIS
ABS system can only be diagnosed using ABS Tester (0000-42-0010). See Fig. 13 . An Adapter Harness
(49N0-66-001) is also required to test Miata ABS system. ABS tester cannot diagnose ABS control unit. If a
malfunction is detected in ABS and all other components in brake system are okay, replace ABS control unit.
If ABS tester is unavailable, test each component of ABS. See test procedures under TESTING. If all ABS
components test okay, replace control unit with a known good unit, and retest system for correct operation.
PRE-DIAGNOSIS INSPECTION
Perform a visual inspection of ABS components that could cause anti-lock problem. Visual inspection may help
identify cause of simple problem.
DIAGNOSTIC PROCEDURE WITH ABS TESTER
ABS tester uses one display window and 2 switches for reading information from unit. Become thoroughly
familiar with ABS tester displays and operation before proceeding. See Fig. 13
. To diagnose ABS system, go
to TESTING SEQUENCE charts under DIAGNOSING ABS SYSTEM. When diagnosing ABS system,
complete tests in order given under TESTING SEQUENCE. If ABS tester does not operate, check fuses,
ignition switch and ignition circuit.
TESTING
NOTE: See BRAKE BLEEDING article in the BRAKES Section.
ApplicationSequence
Miata & 929Longest Line First
RX7RR, LR, RF, LF
(1)If rear caliper has not been disassembled, open upper bleed valve only.
NOTE: Before testing ABS components, ensure battery and charging system are
functioning properly. To prevent damage to ABS control unit connector, use
very thin pins when probing connector.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
Microsoft
Sunday, July 05, 2009 2:17:31 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 2:17:32 PMPage 12 © 2005 Mitchell Repair Information Company, LLC.

Disconnect 2-pin connector at hydraulic unit. Check continuity at hydraulic control between Red/Yellow wire
terminal and ground. If continuity is not present, replace hydraulic control unit. If continuity is present, pump is
okay. Check wiring between hydraulic control and ABS control unit.
Continuity Test (RX7 & 929)
1. Disconnect 12-pin hydraulic unit connector. Using a DVOM, check continuity between Black wire and
ground. If there is continuity, check continuity between Black wire terminal at hydraulic unit connector
and Green wire terminal at 2-pin hydraulic unit connector.
2. If continuity exists, connect hydraulic unit connectors. If continuity is not present, replace wiring harness
between control unit and body ground.
3. Disconnect ABS control unit connector. Check continuity between Green wire of ABS control unit
harness connector and ground. If continuity is present, check for poor connection of ABS control unit
connector or faulty ABS control unit. If continuity is not present, repair open circuit.
VALVE RELAY
Continuity Tests
1. Disconnect negative battery cable. Remove valve relay from hydraulic unit. Using a DVOM, check
continuity between relay terminals "C" and "E" and between terminals "B" and "D". See Fig. 11
.
2. Ensure continuity exists. Connect 12 volts to terminal "B", and ground terminal "D". Check continuity
between terminals "A" and "E". Ensure continuity exists. If continuity is not as specified, replace valve
relay.
WHEEL SPEED SENSORS
Sensor Resistance Test
Disconnect speed sensor connector. Using a DVOM, measure resistance between sensor terminals. Resistance
should be 800-1200 ohms. If resistance is not as specified, replace speed sensor.
Harness Continuity & Voltage Tests
1. With ignition off and speed sensors connected, disconnect ABS control unit connector. Using a DVOM,
check continuity between indicated terminals of ABS control unit harness connector. See WHEEL
SPEED SENSOR TESTS TABLE.
2. If reading on DVOM is not 800-1200 ohms, check wiring harness between wheel speed sensor and ABS
control unit. If DVOM reading is 800-1200 ohms, check voltage between indicated terminals in WHEEL
SPEED SENSOR TESTS TABLE.
3. Turn ignition on. Rotate appropriate wheel one revolution per second by hand to check voltage. If DVOM
does not indicate 50-60 millivolts, replace wheel speed sensor.
WHEEL SPEED SENSOR TESTS
Test Between Control Unit

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
Microsoft
Sunday, July 05, 2009 2:17:32 PMPage 13 © 2005 Mitchell Repair Information Company, LLC.

CHARGING SYSTEM TROUBLE SHOOTING
TROUBLE SHOOTING PRECAUTIONS
Miata
Obtain code number and deactivate audio anti-theft system before disconnecting battery.
All Models
DO NOT reverse battery cable connections. Rectifier will be damaged.
DO NOT use high voltage type testers.
PROBLEM Possible CauseAction
NO START CONDITION
Dead BatteryCheck/Replace Battery
Bad Cable ConnectionsClean/Replace Cables
Ignition Switch/Circuit FaultCheck Switch/Circuit
CHARGING SYSTEM WARNING LIGHT STAYS ON
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Warning Light WiringCheck/Repair Wiring
Faulty Stator/DiodesTest/Repair Alternator
Faulty Voltage RegulatorTest/Repair Regulator
WARNING LIGHT OFF WITH IGNITION SWITCH ON
Blown FuseCheck/Replace Fuse
Faulty AlternatorTest Alternator
Bad Warning Light BulbTest/Replace Bulb
WARNING LIGHT ON WITH IGNITION SWITCH OFF
Alternator Wiring ShortCheck/Repair Wiring
Faulty Rectifier BridgeTest/Repair Alternator
AMMETER INDICATES DISCHARGE
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Faulty AmmeterTest/Replace Ammeter
NOISY Defective BatteryReplace Battery
Defective AlternatorTest/Repair Alternator
Defective RegulatorTest/Repair Regulator
NOTE: Observe the following precautions when trouble shooting or testing charging
system:

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

Battery voltage is always applied to terminal "B".
DO NOT ground terminal "L" while engine is running.
DO NOT start engine with connector disconnected from terminals "L" and "S".
DO NOT apply battery voltage to terminal "L".
ON-VEHICLE TESTING
ALTERNATOR OUTPUT
1. Connect an ammeter (80-amp minimum) in-line between terminal "B" connector and wire. See Fig. 2
,
Fig. 3
and Fig. 4 . Turn all headlights and accessories on and depress brake pedal. With engine operating
at 2500-3000 RPM, measure output amperage. NOTE: Check alternator wiring harness connections and drive belt tension. Battery
must be fully charged before testing. Wait at least 30 seconds after starting
engine before measuring system voltage.
CAUTION: Ensure alternator terminal "B" does not contact ground.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

SWITCHES
SWITCHES LOCATION
MISCELLANEOUS
MISCELLANEOUS LOCATION
COMPONENT LOCATION GRAPHICS
ComponentLocation
Idle Speed Control SolenoidOn throttle body.
Purge Control Solenoid ValveOn right side of engine compartment, on shock
tower.
ComponentLocation
A/C Pressure SwitchOn high pressure refrigerant line.
Back-Up Light SwitchOn left side of transmission.
Clutch SwitchOn bracket, above clutch pedal. See Fig. 2 .
Neutral SwitchOn right rear side of transmission. See Fig. 2 .
Parking Brake SwitchOn base of parking brake lever.
Power Steering Pressure SwitchOn power steering housing assembly. See Fig. 2 .
Seat Belt Buckle SwitchOn driver's side seat belt buckle.
Stoplight SwitchOn bracket, above brake pedal. See Fig. 2 .
ComponentLocation
Diagnostic Check ConnectorOn left rear of engine compartment, near master cylinder. See Fig. 2 .
IgniterOn right rear corner of engine compartment, near fuse/relay block. See
Fig. 2
.
SRS Back-Up BatteryMounted below SRS control unit. See Fig. 3 .
NOTE: Figures may show multiple component locations. Refer to appropriate table for
proper figure references.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
Microsoft
Sunday, July 05, 2009 2:15:23 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

FUSES & CIRCUIT BREAKERS
Fuses & Circuit Breakers 1990-95 Mazda
FUSES & CIRCUIT BREAKERS
FUSE PANEL LOCATION
Fuse box is located above driver's left knee, accessible through a removable cover. The main fuse block is
located at the right rear of the engine compartment.
The Trunk Mounted Fuse Panel is located on the right side of the trunk, near the trunk hinge. (1992-95 Models)
MAIN FUSE BLOCK IDENTIFICATION
Fig. 1: Main Fuse Block Identification

Courtesy of MAZDA MOTOR OF AMERICA, INC.
Fuse & Circuit Breaker Identification
WARNING:Always disconnect battery ground cable before servicing "high-current"
fuses. It is recommended that "high-current" fuses be replaced by a
qualified technician.

1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda

1991 Mazda MX-5 Miata
FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1990-95 Mazda
Microsoft
Sunday, July 05, 2009 2:15:54 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
Microsoft
Sunday, July 05, 2009 2:15:57 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 2:15:54 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 2:15:54 PMPage 6 © 2005 Mitchell Repair Information Company, LLC.

ADJUSTMENTS
AIRFLOW MODE DOOR
Set airflow mode control lever to vent position. Disconnect control cable at airflow mode door lever. Extend
airflow mode door lever until it stops, and hold it there. See Fig. 1
. Attach control cable to door lever and clip.
Ensure control lever moves freely between defrost and vent positions.
AIR-MIX (TEMPERATURE BLEND) DOOR
Set temperature control lever to maximum hot position. Disconnect control cable at air-mix door lever. See Fig.
1 . Extend air-mix door lever until it stops, and hold it there. Attach control cable to door lever and clip. Ensure
control lever moves freely between hot and cold positions.
RECIRCULATED/FRESH AIR DOOR
Set recirculated/fresh air control lever to fresh position. Disconnect control cable at recirculated/fresh air door
lever. Retract recirculated/fresh air door lever until it stops, and hold it there. Attach control cable to door lever
and clip. Ensure control lever moves freely between recirculated air and fresh air positions.
TESTING
BLOWER MOTOR CIRCUIT
1. Check 30-amp HEATER circuit breaker in passenger compartment fuse panel. If Red button has not
popped out, go to next step. If Red button has popped out, repair short circuit and press Red button to
reset circuit breaker.
2. Turn ignition on. Turn blower switch to 4th position (high). Check voltage at Blue wire terminal of 2-
wire blower motor connector on bottom of blower case. If no voltage is present, repair wiring between
circuit breaker and blower motor.
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 volta
ge is present, replace blower resistor. If battery voltage is present, check voltage at Blue/Red 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.
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
HEATER SYSTEM 1990-92 Heater Systems
Microsoft
Sunday, July 05, 2009 2:12:14 PMPage 2 © 2005 Mitchell Repair Information Company, LLC.