Why won't my car heater shut off

The most common reasons an INFINITI I35 heater isn't working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.

INFINITI I35 Heater Is Not Working - RepairPal.com

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check to make sure the blend door is changing from cold to hot. With the engine off and the key in the run position set the blower motor to the highest speed. Turn the temp dial to full cold and wait 30 seconds. Now turn the temp dial to full hot a listen carefully. You should hear a difference in sounds as the blend door sweeps through its full range.

If it is working and the engine is fully warmed up feel the heater hoses where the pass through the fire wall. One should be very hot and the other should be pretty warm. If one is hot and one is significantly cooler than either the heater core is plugged or there is air in the heater core causing a block in flow.

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check the resister its the part the harness plugs into

Faulty heater control valve.Its located under the hood on the passenger side in front of the firewall.

there is a vacuum ran valve on your heater hoses goin in to your heater core on the fire wall, they tend to get stuck shut n dont open to let hot anti freeze in the heater core, so cold air right, qwik fix is find the valve on heater core inlet and wire tie it open so antifreeze circulates no matter what, this is known on ford explorers. pretty much same truck.

replace water pump on first question,second replace the speed switch.










TIM..

the blend door actuator is bad

you might check your switch sounds like to me that your two lower speed sides of the switch maybe burnwed out.

heater blower motor risister most likely cause. should be under dash near heater motor.

fan motor will not shut off