INSUFFICIENT HEATING
Component Function Check
SYMPTOM: Insufficient heating
Inspection FLOW
- CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - TEMPERATURE INCREASE
- Turn temperature control dial clockwise to maximum heat.
- Check for hot air at discharge air outlets. Can a symptom be duplicated?
YES >> GO TO 3
NO >> GO TO 2
- CHECK FOR ANY SYMPTOMS Perform a complete operational check and check for any symptoms. Refer to See: Initial Inspection and Diagnostic Overview\Inspection And Adjustment\Description And Conditions\Manual Air Conditioner.
Does another symptom exist?
YES >> Refer to See: Symptom Matrix Chart.
NO >> System OK.
- CHECK FOR SERVICE BULLETINS Check for any service bulletins.
>> GO TO 4
- CHECK ENGINE COOLING SYSTEM
- Check for proper engine coolant level. Refer to See: Engine, Cooling and Exhaust\Cooling System\Coolant\Testing and Inspection (QR25DE) or See: Engine, Cooling and Exhaust\Cooling System\Coolant\Testing and Inspection (VQ35DE).
- Check hoses for leaks or kinks.
- Check radiator cap. Refer to See: Engine, Cooling and Exhaust\Cooling System\Coolant\Testing and Inspection (QR25DE) or See: Engine, Cooling and Exhaust\Cooling System\Coolant\Testing and Inspection(VQ35DE).
- Check for air in cooling system. >> GO TO 5
- CHECK AIR MIX DOOR MOTOR OPERATION Check and verify air mix door mechanism for smooth operation.
Does air mix door operate correctly?
YES >> GO TO 6
NO >> Check the air mix door motor circuit. Refer to See: Component Tests and General Diagnostics\Air Mix Door\Manual Air Conditioner.
- CHECK AIR DUCTS Check for disconnected or leaking air ducts.
Is the Inspection result normal?
YES >> GO TO 7
NO >> Repair all disconnected or leaking air ducts.
- CHECK HEATER HOSE TEMPERATURES
- Start engine and warm it up to normal operating temperature.
- Touch both the inlet and outlet heater hoses. Is the Inspection result normal?
YES >> Hot inlet hose and a warm outlet hose: GO TO 8
NO >> Both hoses warm: GO TO 9
- CHECK ENGINE COOLANT SYSTEM Check thermostat operation. Refer to See: Engine, Cooling and Exhaust\Cooling System\Coolant Outlet\Service and Repair (QR25DE) or See: Engine, Cooling and Exhaust\Cooling System\Coolant Outlet\Service and Repair (VQ35DE).
Is the Inspection result normal?
YES >> System OK.
NO >> Repair or replace as necessary.
- CHECK HEATER HOSES Check heater hoses for proper installation.
Is the Inspection result normal?
YES >> System OK.
NO >> 1. Back flush heater core.
- Drain the water from the system.
- Refill system with new engine coolant. Refer to See: Engine, Cooling and Exhaust\Cooling System\Coolant\Service and Repair(QR25DE) or See: Engine, Cooling and Exhaust\Cooling System\Coolant\Service and Repair (VQ35DE).
- To retest GO TO 10
- CHECK HEATER HOSE TEMPERATURES
- Start engine and warm up to normal operating temperature.
- Touch both the inlet and outlet heater hoses. Is the Inspection result normal?
YES >> System OK.
NO >> Replace heater core Refer to See: Heater Core\Service and Repair.
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