Air Select Knob; Air Source Select Lever; Fan Control Knob; Temperature Control Knob - Isuzu Trooper 1999 Workshop Manual

1A–6 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Air Select Knob

The air select knob allows you to direct heated air into the
passenger compartment through different outlets.
1. Vent – In this position, air is discharged from the
upper air outlet. Air quantity is controlled by the fan
control knob.
2. Bi-Level – In this position, air flow is divided between
the upper air outlets and the floor air outlets, with
warmer air delivered to the floor outlets than the air
delivered to the upper air outlets.
3. Foot – In this position, air flow is delivered to the foot
while sending approx 30% op total amount air to the
wind shield.
4. Def/Foot – In this position, air flow is delivered to the
foot, while sending approx. 40% of total amount of air
to the windshield.

Air Source Select Lever

The intake of outside air and the circulation of inside air
are controlled by sliding this lever left or right.

Fan Control Knob

This knob controls the blower motor speed to regulate the
amount of air delivered to the defrost, foot, and ventilation
ducts:
1. Low
2. Medium Low
3. Medium High
4. High
Selecting this mode allows air conditioning system to
work when the fan switch is turned to on position,
even if the A/C switch is off.
5. Defrost – In this position, most of the air is delivered
to the windshield and a small amount is delivered to
the side windows.
Moving the air source select lever to the "CIRC" position
provides quickest heat delivery by closing the blower
assembly mode door. In this position, outside air is not
delivered to the passenger compartment.
Selecting this mode allows air conditioning system to
work when the fan switch is turned to on position, even if
the A/C switch is off.

Temperature Control Knob

When the temperature control knob is in the "COLD"
position, the air mix door closes to block the air flow to the
heater core.
When the temperature control knob is in the "HOT"
position, the air mix door opens to allow air to pass
through the heater core and heat the passenger
compartment
Placing the knob in a intermediate position will cause a
lesser or greater amount air to reach the heater core. In
this mode the passenger compartment temperature can
be regulated
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