1991 ACURA NSX Service Repair Manual

Supplemental Restraint System (SRS)
Self-diagnosis Function

The SRS unit includes a self-diagnosis function. If there
is a failure in the sensors, SRS unit, inflator, or their cir-

cuits, the SRS light in the instrument panel goes ON.

SRS INDICATOR LIGHT
As a system check the SRS light also comes on when

the ignition is first turned to the II position. If the light
goes off after approximately 6 seconds, the system is

OK.

If the SRS light remains on (or fails to come on the sys-

tem check mode) one of the SRS components (or the wir-
ing/connectors in-between) is faulty.

Troubleshooting Precautions Always use the test harness. Do not use test
probes directly on component connector
terminals or wires; you may damage them or the
control unit. When connecting any of the test harnesses to the
system, push the connectors straight-in; do not
bend the connector terminals. Before disconnecting any part of the SRS wire
harness, install the short connector (RED) on the airbag. SRS Indicator Light Troubleshooting
Possible conditions: 1. SRS light does not come on at all — see page
23-326.

2. SRS light stays on constantly - see page 23-330.

3. SRS light comes on in combination with a failure of
another electrical system (brake indicator, engine
check light etc.). Check for damage/corrosion at the
dash fuse box.

NOTE:
Before starting the applicable troubleshooting,
check the condition of all SRS connectors and
ground points. If the fault is not found after completing the ap-
plicable troubleshooting, substitute a known-good

SRS unit and check whether the light indication

goes away.
Short connector Installation 1. Disconnect the battery negative cable, then the positive cable.
2. Remove the access panel from the steering wheel, then remove the short connector (RED).
SHORT
CONNECTOR
(RED)

3. Disconnect the connector between the airbag and cable reel, then install the short cconnector (RED)
on the airbag.
Troubleshooting

SHORT CONNECTOR (RED)
AIRBAG CONNECTOR

CABLE REEL

CONNECTOR
ACCESS

PANELProCarManuals.com

Under-Dash Fuse Box

Removal/Installation

CAUTION;

Be sure to install the SRS wiring so that it is not

pinched or interfering with other car parts.

Always keep the short connector on the airbag con-

nector when the harness is disconnected.

Removal:

1. Disconnect both the negative cable and positive ca-

ble from the battery.

2. Remove the maintenance lid A below the airbag,

then remove the short connector.

SHORT CONNECTOR

MAINTENANCE LID A

3. Disconnect the connector between the airbag and

cable reel.

4. Connect the short connector to the airbag side of

the connector.

STEERING WHEEL

AIRBAG CONNECTOR

CABLE REEL CONNECTOR

SHORT CONNECTOR (RED)
5. Remove the door sill molding.

6. Remove the kick panel trim pieces, as necessary.

7. Remove the under-dash fuse box mounting bolts.

8. Disconnect the under-dash fuse box connectors.

NOTE: The SRS main harness connector is double

locked. To remove it, first lift the connector lid with

a thin screwdriver, then press the connector tab

down and pull the connector out.

9. Take out the under-dash fuse box.

TAB

SRS FUSE

No. 1 (10 A)

SRS MAIN HARNESS
KICK PANEL TRIM

LIDProCarManuals.com

Installation:

1. Install the under-dash fuse box.

KICK PANEL TRIM

2. Connect the connectors to the under-dash fuse box.

NOTE: To reinstall the SRS main harness connector,

push it into position until it clicks, then close the con-

nector lid.

3. Install the kick panel trim pieces.

4. Disconnect the short connector from the airbag.

SHORT

CONNECTOR

(RED)

MAINTENANCE

LID A

CABLE REEL

CONNECTOR

AIRBAG CONNECTOR

SHORT CONNECTOR
5. Connect the airbag 2-P connector and cable reel 2-P

connector.

6. Attach the short connector to the lid A and attach

to the steering wheel.

7. Connect both the negative cable and positive cable

to the battery.

8. After installing the under-dash fuse box, confirm that

all systems work properly.ProCarManuals.com

Steering Lock Replacement

SRS wire harness is routed near the steering lock

assembly.

CAUTION:
All SRS electrical wiring harnesses are covered with
yellow outer insulation.Before disconnecting the SRS wire harness, install
the short connector on the airbag (see page 23-323). Replace the entire affected SRS harness assembly
if it has an open circuit or damaged wiring.


CABLE REEL

SRS MAIN WIRE HARNESS

1. Remove the dashboard lower and center panels.
2. Remove the steering column covers. 3. Remove the knee bolster and dash lower frame.
4. Disconnect the 7-P and 6-P connectors.

DASH LOWER FRAME
KNEE BOLSTER
(cont'd)
NOTE: The illustration shows A/T.
6. Lower the steering column assy.
7. Center punch each of the shear bolts and drill their
heads off with a 3/16 in. drill bit.

CAUTION: Do not damage the switch body when
removing the shear bolt head.
8. Remove the shear bolts from the switch body.
39 N·m

(3.9 kg-m, 28 Ib-ft)
16 N·m

(1.6 kg-m. 12 Ib-ft)

4. Remove the column holder mount bolts.
5. Remove the mounting nuts.ProCarManuals.com

Ignition Switch

Steering Lock Replacement (cont'd)

9. Insert the key and turn it to "1".

NOTE: The illustration shows A/T.

STEERING LOCK

BODY

LOCK PIN

10. Push the lock pin and pull out the steering lock as-

sembly.

TWIST-OFF PORTION
SHEAR BOLT
11. Turn the key to "1", push the pin and insert the

steering lock assembly into the steering column

until it clicks into place.

12. Loosely tighten the new shear bolt.

NOTE: Make sure the projection on the ignition

switch is aligned with the hole in the steering

column.

13. Insert the ignition key and check for proper opera-

tion of the steering wheel lock and that ignition key

turns freely.

14. Tighten the shear bolt until the hex head twists off.ProCarManuals.com

Radiator and Condenser Fan Controls

Description

Fan control system:

The cooling fan system is comprised of radiator fan, condenser fan (left, right), engine compartment fan, radiator fan
low relay, radiator fan high relay, condenser fan relay, engine room fan relay, radiator fan resistor, coolant temperature

sensor, A/C pressure switch, cooling fan control unit, climate control unit, and PGM-FI ECU.

The fan control unit controls the operation of the radiator fan and condenser fan.
It uses inputs from the coolant temperature sensor and A/C pressure switch (A and B) on the A/C system to determine

when the fans should run and at what speed.
Additionally, the temperature switch shuts down the A/C system if the coolant temperature exceeds 130°C (266°F).
If the pressure in the A/C system is higher than normal, pressure switch A closes and the fans will run at high speed only.

See the A/C section for description and specification of that funciton.

Fans operating condition:ProCarManuals.com

Troubleshooting

NOTE: The numbers in the table show the troubleshooting sequence.
*: Refer to section 22 for A/C pressure inspection of the A/C systemProCarManuals.com

Speedo/Tripmeter/Odometer

Troubleshooting

NOTE: The numbers in the table show the troubleshooting sequence.
PRINTED CIRCUITPANEL A

JOINT CONNECTOR PRINTED
CIRCUIT PRINEL B
View from the back of the gauge assembly.ProCarManuals.com