1991 MAZDA MIATA wiring

Blower motor relay supplies power to blower motor. Blower resistor determines blower speed. With blower
switch in highest position, blower motor is grounded through blower switch. With blower switch in all other
positions, blower motor is grounded through blower resistor and blower switch.
Circuit through compressor clutch is completed when A/C relay is energized and pressure switch is closed. A/C
relay is energized when Engine Control Unit (ECU) unit grounds the solenoid circuit of the relay. The ECU
energizes A/C relay if evaporator thermoswitch is closed and A/C and blower switches are on. The ECU also
controls A/C relay operation according to engine load.
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
AIR BAG WARNING
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. 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
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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.

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. 4
. To install, reverse removal procedure.
Fig. 4: Exploded View of Instrument Panel

Courtesy of MAZDA MOTORS CORP.
WIRING DIAGRAMS

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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Fig. 5: Manual Heater-A/C System Wiring Diagram (1990)
Fig. 6: Manual Heater
-A/C System Wiring Diagram (1991)

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 10 © 2005 Mitchell Repair Information Company, LLC.

Fig. 7: Manual Heater-A/C System Wiring Diagram (1992)

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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STARTER - DIRECT DRIVE
1990-92 ELECTRICAL Mazda Starters - Direct Drive
DESCRIPTION
Nippondenso direct drive starter is a conventional 12-volt, 4-pole, brush-type starter. The integral solenoid is
attached to the drive housing. The overrunning clutch pinion drive is mounted directly on armature shaft drive
end.
TROUBLESHOOTING
TESTING (ON VEHICLE)
CIRCUIT TESTING
1. Turn ignition switch to START position, depress clutch and ensure starter operates. If starter does not
operate, use voltmeter to check voltage at "S" terminal when clutch is depressed and ignition is turned to
START position. See Fig. 1
.
2. If voltage is less than 8 volts, check starter interlock switch and ignition switch to starter wiring circuit for
short to ground. If voltage is greater than 8 volts and starter is inoperative, starter has an internal fault.
Repair or replace as required. NOTE: For information on B2200 and Protege models with automatic transmissions,
see STARTERS - GEAR REDUCTION article.
NOTE: See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL
INFORMATION section.
NOTE: Before testing, ensure battery is fully charged, battery cables and terminals are
clean and tight and engine grounds are good.

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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to field coil housing. If continuity exists, repair or replace field coil.
OVERRUNNING CLUTCH PINION DRIVE
Hold overrunning clutch housing and turn pinion gear by hand. If pinion turns in both directions, clutch is faulty
and must be replaced. DO NOT clean overrunning clutch with solvent, as it is packed with grease and sealed by
manufacturer.
REMOVAL & INSTALLATION
1. Disconnect negative battery cable. Raise vehicle on hoist. Remove undercover. Disconnect wiring from
starter. Remove differential lock assembly (4WD models). On Protege (M/T) and 323 models, remove
support brace from under intake manifold. Remove starter mounting bolts. Remove lowest mounting bolt
last. Remove starter from under side of vehicle.
2. To install starter, reverse removal procedure. Tighten mounting bolts to 23-24 ft. lbs. (31-46 N.m).
Tighten battery terminal nut to 87-104 INCH lbs. (9.8-12 N.m).
OVERHAUL
DISASSEMBLY & ASSEMBLY
1. Mark rear cover, field coil housing and front drive housing for reassembly reference. Remove solenoid
and shims, rear cover and brush plate. Remove field coil housing and pull armature and yoke lever from
front drive housing. See Fig. 4
& Fig. 5. Use arbor press to remove circlip, stopper and pinion drive from
armature shaft. See Fig. 6
.
2. To assemble, reverse removal procedures. Lubricate solenoid plunger, yoke lever and armature bushings.
Use arbor press and pinion drive to install stopper and circlip on armature shaft. See Fig. 6
. Ensure brush
plate, rear cover and field coil housin
g are aligned when installing through bolts.

1991 Mazda MX-5 Miata
STARTER - DIRECT DRIVE 1990-92 ELECTRICAL Mazda Starters - Direct Drive
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Courtesy of MAZDA MOTORS CORP.
Removal & Installation (MPV, MX-6 & 626)
1. Remove steering wheel and combination switch. See STEERING WHEEL & HORN PAD and
COMBINATION SWITCH
under REMOVAL & INSTALLATION. Remove steering lock assembly.
See IGNITION SWITCH & STEERING LOCK
under REMOVAL & INSTALLATION.
2. Remove lower dash panel and A/C duct. Remove lower column cover and steering shaft-to-intermediate
shaft "U" joint bolt. On MPV with A/T, remove shift lever mechanism.
3. On all models, separate steering shaft from intermediate shaft. Remove steering column upper bracket
bolts. Remove steering column. To install, reverse removal procedure. Tighten bolts to specification. See
TORQUE SPECIFICATIONS TABLE
at end of article.
OVERHAUL
STEERING COLUMN
Disassembly
Remove wiring and switches. Clamp column in vise. Turn steering shaft to remove. With a hammer and chisel,
make a groove in steering lock assembly shear screws. Remove shear screws. Remove steering lock.
Inspection
Check all components for damage or wear. Check steering shaft for bends, damage or sheared plastic pins.
Check bearings for excessive play. Replace parts as necessary. Measure length of steering shaft. See Fig. 9
.
Reassembly
To reassemble, reverse disassembly procedure. Grease steering shaft, bushings and bearings. Always use NEW
shear screws.
STEERING SHAFT DIMENSIONS
(1) NOTE: Steering shaft dimension for 929 is not available from manufacturer.
ApplicationLength - In. (mm)
B2200 & B2600i32.69-32.99 (830.0-835.6)
Miata22.09-23.02 (561.1-584.7)
MPV24.05-24.17 (611.0-614.0)
MX-6 & 62624.00-24.05 (609.6-611.1)
Protege & 32323.86-23.94 (606.0-608.0)
RX732.05-32.17 (814.0-817.0)
929(2)
See Fig. 9 for measuring points.

1991 Mazda MX-5 Miata
STEERING COLUMN 1991 STEERING Mazda - Steering Columns
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