1998 HONDA INTEGRA service indicator

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.
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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.

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

- 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

- How the Circuit Works
Do not smoke while working on the fuel system.
Keep open flame away from the work area. Drain
fuel only into an approved container.
A thermistor is mounted in the fuel tank unit. When
the thermistor is cool, its resistance is very high.
When the thermistor is warm, its resistance
decreases. Fuel in the fuel tank transfers heat away
from the thermislor last enough to keep it cool so
the thermistor's resistance stays high and the low
fuel indicator lighl does not come on. When the fuel
level drops below about 2.2 gallons, the thermistor
is no longer immersed in fuel. Without the fuel to
cool it, the thermistor's resistance decreases,
allowing current to flow through the low fuel
indicator light and the thermistor to ground, and lhe
low fuel indicator light comes on.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
74-1

- How the Circuit Works
With the ignition switch in ON (ll) or START (lll),
voltage is applied to the A,/T gear position indicator.
The A,/T gear position switch provides a ground for
each position. As an input is grounded, ils indicator
light comes on. lf you se,ecl B, tor example, ground
will be applied to the input of the A,/T gear position
indicator, and the R indicator bulb will come on.
With the headlight switch in PARK or HEAD, voltage
is applied to the RED/BLK wire terminal. this
changes the indicator panel illumination from lixed
to controlled by the dash lights dimmer inpul
through the RED wire.
When the lransmission ('98.99 models) or
powertrain ('00 model) control module (TCM or
PCM) detects an abnormality in the automatic
transmission control system, or when you request
diagnostic trouble codes through the service
check connector, the TCM or PCM will make lhe D4
indicator light blink.
Refer to the Service Manual (Section 14,
Automatic Transmission) for soecific tests or
troubleshooting procedures.
89-1

Headlights (cont'd)
- How the Circuit Works
Low Beam OperationRefer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
With the headlight switch in HEAD and the dimmer
switch in LO, current flows through the headlight
switch, fuse 21 , tuse 22, and the low beam
filaments to ground, and the low beams come on.
tligh Beam Operation
With the headlight switch in HEAD and the dimmer
switch in Hl, current flows through the headlight
switch, dimmer/passing switch, fuses 4, 5, 21, and
22, and the low and high beam filaments to ground,
and the low and high beams come on.
Current also tlows through the high beam indicator
light to ground. The high beam indicator comes on
to remind the driver that the high beams are on.
Flash operation
The flash feature works with the headlight switch in
OFF, PARK, or HEAD (low beams). When you
move the flash-to-pass switch to ON, current flows
through the switch, fuses 4 and 5, and the high
beam filaments to ground, and the high beams
flash. The high beam indicator also flashes during
the flash oDeration. The flash function has no effect
it the high beams are already on.
Daytime Running Lights Day Operation
When you turn the ignition to ON (ll) with the
parking brake released, the daytime running lights
control unit supplies battery voltage at the
WHT/RED wire. This voltage is applied to the high
beam headlights through the daytime running lights
resistor. Each high beam headlight receives less
than battery voltage causing them to come on al
reduced brightness.
lf the parking brake is set, a ground signal is applied
to the daytime running lights control unit at the
RED/GRN wire. It the parking brake is set when you
first turn the ignition switch to ON (ll), the high beam
headlights will remain off until you release the
parking brake. Once the high beam headlights are
in day mode, setting the parking brake will not
cause the headlights to turn off . When low or high
beam operation is requested, baftery voltage trom
the headlight switch is applied to the daytime
running light control unit via the RED/vVHT wire.
The daytime running light control unit then
discontinues the daytime running light mode.
1 10-10

- How the Circuit Works
The immobilizer system is designed to prevent the
car f rom being started without the owner's ignition
key. lf an attempt is made to start the car without
the correct key, the immobilizer system will disable
the car's fuel supply.
The immobilizer system consists of the ignition key,
immobilizer receiver unit, immobilizer indicator
light, PGM-FI main relay, fuel pump, and the PCM
or ECM.
With the ignition switch in ON (ll) or START (lll), the
immobilizer receiver unit and the PCM or ECM
receive an "ignition on" signal through fuse 44 and
the PGM-FI main relay. The PCM or ECM then
sends power to the ignition key transponder through
the immobilizer receiver unit. The transponder then
sends a coded signal back to the PCM or ECM
through the receiver unit. lf the signal is correct, the
PCM or ECM will energize the car's fuel supply
system by grounding the PGM-FI main relay. The
immobilizer indicator light flashes a code to indicate
that the correct key has been inserted. lf the
ignition key signal is not correct, the PCM or ECM
will not energize the car's fuel supply system by not
grounding the PGM-Fl main relay. The immobilizer
indicator light then flashes a code to indicate that an
incorrect key has been inserted.
Refer to the Service Manual (Section 23,
Body Electrical) for specific tests and
troubleshooting procedures.
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