1991 MAZDA MIATA fuse

AIR BAG RESTRAINT SYSTEM
MAZDA 1990-91 AIR BAGS
DESCRIPTION & OPERATION
The air bag restraint system, when used in conjunction with seat belt, provides increased protection for the
driver in a collision. The air bag restraint system consists of the following: AIR BAG warning light, air bag
module, clockspring connector, diagnostic module, crash sensors, back-up battery, and wiring harnesses.
The air bag is designed to deploy when rear safing sensor and at least one front impact sensor close in a
collision, and ignition switch is in the ON position. The back-up battery supplies current for the ignitor if the
vehicle battery or fuses fail during a collision. The diagnostic module monitors the air bag system for failures. I
f
any failures are detected by the module, the driver is warned of such failure(s) through the activation or flashing
of the AIR BAG warning light.
SERVICE PRECAUTIONS
Disable air bag system before servicing any air bag system or steering column component. See
DISABLING & ACTIVATING AIR BAG
SYSTEM
Wait about 10 MINUTES after disabling air bag system before servicing. Air bag system voltage is
maintained for about 10 MINUTES after system is disabled. Failure to wait 10 MINUTES before
servicing system may cause accidental air bag deployment and possible personal injury.
On Miata, obtain radio code number from customer and deactivate radio anti-theft function before
disconnecting battery.
Because of the critical system operating requirements, DO NOT service any air bag system component.
Corrections are made by replacement only.
DO NOT use an ohmmeter to check resistance of air bag module, as it may cause air bag deployment.
When carrying a live (undeployed) module, ensure trim cover is pointed away from your body. This
minimizes chance of injure in the event ofaccidental air bag deployment.
When placing a live air bag module on any surface, always face trim cover upward to reduce motion of
module if it is accidentally deployed.
If an open circuit is present, replace entire wiring harness. DO NOT attempt wire repair.
Impact sensors must always be installed with arrow marks facing front of vehicle. Also, check sensors for
cracks, defects or rust before installation. Replace impact sensor(s) if required.
Air bag system clockspring MUST be aligned in the neutral position, since its rotation ability is limited.
DO NOT turn steerin
g wheel or column after removal of steering gear. WARNING:To avoid injury from accidental air bag deployment, read and carefully
follow all WARNINGS and SERVICE PRECAUTIONS.
NOTE: The following precautions should be observed when working with air bag
systems.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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TORQUE SPECIFICATIONS
DIAGNOSIS & TESTING
SELF-DIAGNOSTIC SYSTEM
Trouble Shooting
AIR BAG warning light flashes are used to diagnose air bag system. The number of warning light flashes
depends on the type of fault being detected. Codes are prioritized so that if 2 or more faults are present, the
highest test-priority fault indication will remain until corrected.
Warning Light Does Not Illuminate
Check for blown fuses, burned-out bulb, disconnected diagnostic module, or open circuit between warning light
and diagnostic module.
Warning Light Flashes Or Remains On
Check code output of AIR BAG warning light. See AIR BAG FLASH CODES table.
AIR BAG FLASH CODES
ApplicationFt. Lbs. (N.m)
Air Bag Module Nuts12-15 (16-20)
Steering Wheel Nut29-36 (39-49)
INCH Lbs. (N.m)
Front Impact Sensor Bolts78-113 (9-13)
Rear Safing Sensor Nuts
Miata78-113 (9-13)
RX761-87 (7-10)
WARNING:Follow air bag service precautions to prevent accidentalair bag
deployment and personal injury. See SERVICE PRECAUTIONS.
NOTE: After component replacement, check system to ensure proper operation. See
SYSTEM OPERATION CHECK.
PriorityFlash CodeCause/Diagnosis
1Remains OnFaulty Diagnostic Module
Poor Connection Of Diagnostic
Module Connector (See
DIAGNOSTIC TEST NO. 1)
2Flashes 3 TimesOpen Circuit
Poor Connection Of Power Source

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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DIAGNOSTIC TEST NO. 1
Warning Light Remains On
Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Ensure diagnostic module
connectors are properly connected. If connector is okay, replace diagnostic module.
DIAGNOSTIC TEST NO. 2
Warning Light Flashes 3 Times
1. Measure battery voltage. If voltage is less than 9 volts, charge battery. If battery voltage is okay, check
fuses/relays in order given in FUSE/RELAY LOCATION table. See Fig. 6
or Fig. 7 .
2. If fuses and relays are okay, disable air bag system. See DISABLING & ACTIVATING AIR BAG
SYSTEM. Ensure back-up battery connector is properly connected. If connection is okay, disconnect
back-up battery connector.
Circuit (See DIAGNOSTIC TEST
NO. 2)
3Flashes 5 TimesFaulty Front Impact Sensor (See
DIAGNOSTIC TEST NO. 3)
4Flashes 10 TimesFaulty Diagnostic Module (System
Down-Fused Burned) (See
DIAGNOSTIC TEST NO. 4)
5Flashes 4 TimesFaulty Rear safing Sensor (See
DIAGNOSTIC TEST NO. 5)
6Flashes 6 TimesFaulty Air Bag Module
Poor Connection Of Clockspring
Connector (See DIAGNOSTIC
TEST NO. 6)
7 (1) Flashes 7 TimesPoor Wiring Harness Ground (See
DIAGNOSTIC TEST NO. 8)
8Flashes 8 TimesPoor Ground Of Front Impact
Sensor (See DIAGNOSTIC TEST
NO. 8)
9Flashes 9 TimesOpen Circuit Between Diagnostic
Module and Front Impact Sensor
(See DIAGNOSTIC TEST NO. 3)
10Flashes 2 TimesPoor Ground Of All Front Impact
Sensors (See DIAGNOSTIC TSET
NO. 7)
(1)Code 7 Does not apply to 1990 Miata

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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3. Reconnect negative battery cable. Measure voltage between Green/Red wire of back-up battery connector
and ground. See Fig. 8
or Fig. 9 . If voltage is zero volt, replace wire harness assembly.
4. If battery voltage is present, disconnect negative battery cable and diagnostic module Black and Gray
connectors. See Fig. 10
or Fig. 11 . Reconnect negative battery cable. Measure voltage between
White/Green wire of Gray diagnostic module connector and ground. If voltage is zero volt, replace wire
harness assembly.
5. If battery voltage is present, measure voltage between Green/Yellow wire of Gray diagnostic module
connector and ground. If voltage is zero volt, replace wire harness assembly. If battery voltage is present,
replace diagnostic module.
FUSE/RELAY LOCATION
Fuse/RelayLocation
Miata
Air Bag (15 Amps)In Fuse Block
Air Bag (10 Amps)In Main Fuse Block
Engine (15 Amps)In Fuse Block
INJ (30 Amps)In Main Fuse Block
RX7
Air Bag (15 Amps)In Fuse Block
Air Bag (30 Amps)In Main Fuse Block
Engine (30 Amps)In Main Fuse Block
Wiper (15 Amps)In Fuse Block

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Fig. 6: Identifying Fuses & Relays (Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Fig. 7: Identifying Fuses & Relays (RX7)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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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
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Fig. 7: Locating JC-02 Connector
Courtesy of MAZDA MOTORS CORP.
ANTI-LOCK WARNING LIGHT
Operational Test (Miata)
1. Start engine, and observe ANTI-LOCK light. Light should illuminate for a few seconds. If light does not
illuminate as described, remove instrument cluster. Connect 12 volts to terminal 2k of instrument cluster.
See Fig. 8
. Using a jumper wire, connect terminal 1K of instrument cluster to ground. ANTI-LOCK light
should illuminate. If light does not illuminate, check bulb. If bulb is okay, check meter fuse and wiring
harness.
2. Install instrument cluster, and recheck warning light operation. If light still does not illuminate for a few
seconds, check wiring harness between ANTI-LOCK light and control unit and between ANTI-LOCK
light and hydraulic unit. Check operation of hydraulic unit valve relay.
Operational Test (RX7)

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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