Hummer H1 Service Manual page 729

11-10 Heating/Ventilation/Air Conditioning (HVAC)
Condition
No Air Flow from Outlets
Air Flows from Incorrect
Outlets
Low-Weak Air Flow from
Outlets
Condition
Water on Passenger Side
Floor
Musty Smell
Air Flow Diagnosis
Possible Cause
1. Blower motor fuse blown.
2. Blower motor harness damage (short,
open, loose connection).
3. Blower motor fault.
4. Blower motor resistor fault.
1. Actuator motor or linkage fault.
1. Restriction in air ducts.
2. Restriction in intake hose into main unit.
3. Blower motor fault.
4. Misadjusted or binding mode door linkage.
A/C System Diagnosis
Possible Cause
1. Evaporator drain hose plugged or installed
incorrectly.
2. Coolant leak from heater core.
3. Road splash entering compartment through
evaporator/heater core opening, or through
intake air inlet area.
4. Water leaking into passenger compartment.
1. Water leaking into passenger compartment.
2. Evaporator drain partially or fully plugged.
3. Mold-Mildew development on evaporator
surface, coils, fins.
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Correction
1. Replace fuse.
2. Check harness continuity with ohmmeter
and repair as needed.
3. Run 12V jumper directly to motor. Motor
should run at high speed. If motor fails to
run, replace it. If motor runs, check
resistor.
4. Replace resistor if motor runs when
resistor is bypassed or if blower runs at
high speed setting but will not run at one
or all of the lower settings.
1. Remove passenger side trim to expose
both actuator motors and observe linkage
operation. Adjust linkage if required.
Replace either motor and/or linkage if
inoperative.
1. Repair as needed.
2. Repair as needed.
3. Replace motor or resistor if either is
inoperative.
4. Adjust as necessary.
Correction
1. Open hose with utility knife or tirm end off
hose. Make sure routing of hose is to out-
side of passenger compartment.
2. Replace core if leaking. Replace clamps or
hoses if leaking at heater core connections.
3. Water test and seal off as needed.
4. Water test and correct leaks.
1. Water test and correct leaks.
2. Open or tirm off drain hose with utility
knife. Correct routing if necessary.
3. Clean evaporator with mild disinfectant
soap or replace evaporator as necessary.
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