1991 MAZDA MIATA wiring

ALTERNATOR & REGULATOR
1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
DESCRIPTION
Alternators are conventional 3-phase, self-rectifying type units containing 6 diodes (3 positive and 3 negative)
which are used to rectify current. See Fig. 1
. An internally-mounted, Integrated Circuit (IC) regulator is used
on all models.
Fig. 1: Charging System Wiring Schematic

Courtesy of MAZDA MOTORS CORP.
ADJUSTMENTS
BELT DEFLECTION
Measure belt deflection in center of longest pulley-to-pulley span. See BELT DEFLECTION
SPECIFICATIONS table. If belt deflection is not as specified, adjust as necessary.
BELT DEFLECTION SPECIFICATIONS
ApplicationDeflection - In. (mm)

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
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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.

B2600i and MPV, remove brake drum and drive axles. See REAR AXLE SHAFTS & BEARINGS. On
Protege 4WD, RX7 and 929, disconnect CV joint drive axles from differential assembly and wire aside.
2. On all models, mark flanges and disconnect drive shaft. Remove ABS sensor (if equipped). On RX7,
remove rear exhaust system and differential mount on left side of pinion flange. Remove hanger mounts
and allow left side to hang down. Disconnect sublinks and remove differential.
3. On Protege 4WD and 929 models, remove differential housing assembly-to-chassis mounting bolts.
Remove differential housing assembly from vehicle. On all models, remove differential carrier-to-
housing nuts. Remove differential carrier.
Installation
To install, reverse removal procedure. Apply Sealant (8527 77 739 ) to carrier mating flange. Align marks made
during removal. Refill differential with correct type and amount of lubricant. Tighten all fasteners to
specification. See TORQUE SPECIFICATIONS
.
Fig. 4: Exploded View of Differential Assembly (RX7)

Courtesy of MAZDA MOTORS CORP.
Removal (Miata)
1. Raise and support vehicle. Drain differential. Mark flanges and remove drive shaft. Note locations and
disconnect wiring harness from Power Plant Frame (PPF). See Fig. 5
.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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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.

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
Microsoft
Sunday, July 05, 2009 2:12:14 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

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

1991 Mazda MX-5 Miata
HEATER SYSTEM 1990-92 Heater Systems
Microsoft
Sunday, July 05, 2009 2:12:14 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.

Fig. 4: Heater System Wiring Diagram (Miata)
Fig. 5: Heater System Wiring Diagram (1992 Miata)

1991 Mazda MX-5 Miata
HEATER SYSTEM 1990-92 Heater Systems
Microsoft
Sunday, July 05, 2009 2:12:14 PMPage 6 © 2005 Mitchell Repair Information Company, LLC.