HEATER AND VENTILATION
1A-3
DIAGNOSIS
DIAGNOSIS TABLE
Trouble
Possible Cause
Remedy
Heater blower fan motor won’t
work even when its switch is
operating position.
Fuse blown
Blower fan motor resistor faulty
Blower fan motor switch faulty
Blower fan motor faulty
Wiring or grounding faulty
Check “HTR” fuse, and check for
short circuit to ground.
Check resistor.
Check blower fan switch.
Replace motor.
Repair as necessary.
Incorrect temperature output.
Control cables broken or binding
Temperature control lever faulty
Position of control cable clamp is faulty
Air damper broken
Air ducts clogged
Water valve faulty
Heater core leaking or clogged
Heater hoses leaking or clogged
Thermostat faulty
Check cables.
Check control lever.
Check and adjust clamp position.
Repair damper.
Repair air ducts.
Replace water valve.
Replace core.
Replace hoses.
Check thermostat.
When mode control lever is
changed, air outlet port is not
changed or lever position
disagree with air outlet port.
Control cables broken or binding
Mode control lever faulty
Position of control cable clamp is faulty
Air damper broken
Air ducts leaking or clogged
Check cable.
Check control lever.
Check and adjust clamp position.
Repair damper.
Repair air ducts.