1998 ACURA INTEGRA ignition

- How the Circuit Works
With the ignition switch in ON (ll) or START (lll),
battery voltage is supplied through fuse 15 and the
BLK//EL wire to the vehicle speed sensor (VSS).
The sensor is grounded by the BLK wire to G101.
The speedometer and other control units in the
circuit supply about 5 volts to the ORN wire. The
vehicle speed sensor (VSS) intermittently grounds
the ORN wire which generates a pulsed signal in it.
The number of pulses per minute increases/
decreases with the speed of the car
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
33-1

Cruise Control (cont'd)
- How the Circuit Works
The cruise control system uses mechanical and
electrical devices to maintain the car's soeed at a
setting selected by the driver.
System Description
The cruise control unit receives command signals
from the cruise control main switch and the cruise
control SevBesume switch. With the ignition switch
in ON (ll) or START (lll), voltage is provided to the
cruise control main switch. When you push the
switch to on, power is provided to the cruise control
unit and the brake switch.
The cruise control unit receives information about
operating conditions from the brake switch, the
ignition control module (lCM), the vehicle speed
sensor (VSS), and the clutch switch (manual
transmission) or the A,/T gear positton switch
(automatic transmission). The cruise control unit
then sends signals to the cruise conirol actuator
which regulates the throttle position to maintain the
selected speed. The control unit compares the
aclual speed of the car to the selected speed. The
control unit then uses the result of that comoarison
to oDen or close the throttle.
The brake switch releases the system's control of
the throttle at the instant you press on the brakepedal. The switch sends a signal to the control unit
by removing power from the normally closed brake
input (GRY wire), and providing power at the
normally open brake input (GRNMHT wire). The
control unit responds by allowing the throttle to
close. The clutch switch or the A/T gear position
switch sends a "disengage" signal to the control unit
that also allows the throttle to close.
The cruise control system will set and automatically
maintain any speed above 25 mph (40 km/h). To set
it, make sure the main switch is on and the switch
indicator is on. Then, after reaching the desired
speed, press the set switch. This sends a "set"
signal to the cruise control unit which, in turn,
controls the cruise control actuator to maintain the
set soeed.
When you push the SET switch and the cruise
control system is on, the "cruise control" ON
indicator lights up.
34-4
You can cancel the cruise control system by
turning the main switch off. This removes power to
the control unit and erases the set sDeed from
memory. lf the system is disengaged temporarily
by the brake switch, or clutch switch, and the car's
speed is still above 25 mph, press the RESUME
switch: the car will automatically return to the
previously set speed.
For gradual acceleration without pressing the
accelerator pedal, push the RESUME switch and
hold it there. This will send an "acceleration" signal
to the control unit. When you release the switch, the
system will be reprogrammed tor the new speed. To
slow the car down, push the SET switch in and hold
it there. This sends a "deceleration" signal to the
control unit, causing the car to coast. When the
desired speed is reached, release the SET switch.
This reprograms the system for the new speed.
Reter to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.

Supplemental Restraint System (SRS)
FUSE 13FUEL PUIIP(SRS UNF)t5a
FUS€ 23(s8s)
ts13t5" To avoid accidental deployment and possible iniury,
lq9Fr. always disconnect the driver's airbag and frontg[f" pas"Lnger's airbag connectors (automaticallyPHorQ 58 shorted) before working near any SRS witing.
CAUTION: Whenever the ignition switch is ON (ll), ol
has been turned OFF tor less than three minutes, be
careful not to bump the SRS unit; the airbags could
accidentally deploy and cause damage or iniuries.
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NED

A/C Gompressor Controls (conrd)
- How the Circuit Works
Battery voltage is supplied through fuse 56 to the
A,/C compressor clutch relay contacts at all times.
With the ignition switch in ON (ll), voltage is applied
to the coil of the A,/C compressor clutch relay
through fuse 17. When you push the A,/C switch
ON, and the heater fan switch is in posation 1, 2, 3,
or 4, a "ground" input is provided to the engine or
powertrain control module (ECM or PCM) through
the A,/C thermostat and the A,/C pressure switch.
The A,/C compressor clutch relay is grounded by the
engine or powertrain control module (ECM or PCM).
When energized, the A,/C compressor clutch relay
allows battery voltage to turn on the A,/C
comDressor clutch,
The A,/C ON indicator light comes on when the A"/C
system is requested.
A,/C Thermostat
The A,/C thermostat is located on the evaoorator
housing. The AJC thermostat turns off the A,/C
compressor clutch if the temperature at the
evaporator goes below 3'C (37'F). This prevents
condensation from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. The blower motor will keep running
when the sensor lurns off the compressor.
A,/C Pressure Switch
The A,/C pressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high pressure liquid state. The switch
will sense abnormally high or low pressure, and
open the circuit. This removes ground, and the
compressor will stop running.
Refer to the Service Manual (Section 22,
Air Conditioning) for specific tests or
troubleshooting procedures.
62-2

Fans (cont'd)
- How the Gircuit Works
When the ignition switch is in ON (ll), voltage is
applied to the coils of the radiator fan relay and the
condenser fan relay (with A,/C) through fuse 17.
Whenever a ground is provided to the radiator fan
relay and condenser fan relay, the relays are
energized, turning on the radiator fan motor and
condenser fan motor. The relays can be grounded
by the radiator fan switch, engine or powertrain
control module (ECM or PCM) (USA), or the A,/C
and heater lan switches via the A'lC pressure switch
and the A,/C lhermostat.
A,/C Thermostat
The A,/C thermostat is located on the evaporator
housing. The A/C thermostat turns oft the A/C
compressor clutch it the temperature at the
evaporator goes below 3'C (37"F). This prevents
condensalion from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. lt the temperature goes below 3'C
(37'F) turning off the A"/C thermostat, and the
BLU/RED wire at the A,/C diode was the only wire
providing ground to the condenser and radiator
fan relays (A,/C switch on, heater fans switch on,
radiator fan switch open, and ECM or PCM fan
controi output not grounded), the relay will
deenergize removing voltage from the condenser
and radiator fan motors causing them to stop
running.
A,/C Pressure Switch
The AJC oressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high pressure liquid state. The A,/C
switch turns off the A,/C compressor clutch if it
senses abnormally high or low pressure. lf the A'lC
pressure switch opens, and the BLU/RED wire at
the A/C diode was the only wire providing ground
to the condenser and radiator fan relays (L/C switch
on, heater fans switch on, radiator lan switch open'
and ECM or PCM fan control output not grounded),
the relay will deenergize removing voltage from the
condenser and radiator fan motors causing them to
stop running.
A./C Diode
This diode orevents the radiator fan switch f rom
grounding the "A'lC ON" input to the engine or
powertrain control module (ECM or PCM).
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
63-3

- How the Circuit Works
Voltage is applied at all times through f use 50 to
the rear window defogger relay. With the ignition
swrtch in ON (ll), voltage is applied through luse
16 to the rear window defogger relay and the
defogger ON indicator.
When you turn the rear window defogger switch to
ON, a path to ground is provided for the rear
window defogger relay and the defogger ON
indicator through the integrated control unit. The
defogger ON indicator light comes on and the rear
window detogger relay contacts close. Voltage is
applied to the detogger grid on the surface of the
rear window and the grid heats the rear window to
remove any fog lrom the glass.
A timer in the integrated control unit will automatically
tum off the defogger atter 20 to 30 minutes.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
64-1

- How the Circuit Works
The low engine oil pressure indicator light works in
two ways: il flashes continuously following a
momentary loss of engine oil pressure, or it comes
on and stays on with a complete loss of engine oil
oressure,
When the engine first starts, before its oil pressure
rises above 4.3 psi, voltage is applied to the closed
and grounded engine oil pressure switch and the
light comes on to test the bulb.
With the engine running, voltage is applied at the
WHT/BLU wire of the integrated control unit. With
normal engine oil pressure, the engine oil pressure
switch is open and the low oil pressure indicator
light does not come on. lf the engine oil pressure
switch closes momentarily (more than 0.5 seconds)
but then opens again, the YEURED wire at the
integrated control unit will sense ground through the
switch. The integrated control unit will then provide
and remove ground for the low oil pressure indicator
light through the YEURED wire. The light will flash
on and off until you turn the ignition switch off. The
flashing feature will not work until 30 seconds after
initial voltage is applied to the WHT/BLU wire of the
oil pressure indrcator llasher circuit. This delay
keeps the low oil pressure indicator light from
coming on during engine warm-up.
lf engine oil pressure falls below 4.3 psi and does
not increase, the engine oil pressure switch will stay
closed. The low oil pressure indicator light will then
come on and stay on.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
72-1

Gauges (cont'd)
- How the Circuit Works
When the ignition switch is in ON (ll) or START (lll),
battery voltage is supplied through fuse 25 to the
gauges in the gauge assembly.
Speedometer and Odometer
The odometer and speedometer drive circuits
receive pulses lrom the vehicle speed sensor
(VSS). The pulse rate increases as the car
accelerates. The frequency and duration of these
input pulses are measured and displayed by the
speedometer, odometer and tripmeter.
Tachometer ('98-'99 Models)
The tachometer drive circuit receives oulses from
the ignition control module (lCM) in the distributor
assembly. The solid-state tachometer then displays
these pulses as engine speed. For each 200 pulses
per minute from the ignition control module (lCM),
the tachometer displays 100 RPM.
Tachometer ('00 Model)
The tachometer drive circuit receives pulses f rom
the PCM or ECM. The solid-state tachometer then
displays these pulses as engine speed. For each
200 oulses oer minute trom the PCM or ECM the
tachometer displays 1 00 RPM.
Engine Coolant Temperature Gauge and Fuel
Gauge
The engine coolant temperature gauge has two
intersecting coils wound around a permanent
magnet rotor. Voltage applied to the coils, through
fuse 25, generates a magnetic field. The magnetic
field, controlled by the engine coolant temperature
gauge sending unit, causes the rotor to rotate and
the gauge needle to move. As the resistance in the
sending unit varies, current through the gauge coils
changes. The gauge needle moves toward the coil
with the strongest magnetic tield. The fuel gauge
works the same way.
The engine coolant temperature gauge sending
unit's resistance varies from about 137 ohms at low
engine temperature to between 30-46 ohms at high
temperature (radiator fan running).
The fuel gauge sending unit's resistance varies from
about 2-5 ohms at full, to about 110 ohms at empty.
When you turn the ignition switch to LOCK (0), the
gauge remains at the last reading until you turn lhe
ignition switch to ON (ll) or START (lll) again.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
81'2