Heater control valves are easily diagnosed by observing whether the valve responds when the temperature selector is adjusted.
If there is movement at the valve, but no change in heat, the valve will be removed and inspected. The valve may just be failing to move, or it may be leaking engine coolant. In both cases, the heater control valve is replaced with a high-quality or OEM part.
How is a heater control valve replaced?
The heater control valve is separated from the heater core hoses and control mechanism, which could be a vacuum line or a cable. Then the valve is removed from the firewall, and replaced.
Installation is the reverse of removal, and some adjustment may be necessary if you're dealing with a cable-type controller. After the repair, the engine coolant should be filled and bled of air.
RepairPal recommendations for heater control valve issues
This is a good time to check the heater core hoses and replace them if they're leaking or corroded. A thorough cleaning inside the heater hose ends usually helps prevent a leak. It's also a smart time to check the condition of the coolant.
There are many brands of heater control valves, and many are universal. Low-quality heater control valves may fail prematurely, leading to the same repair in the future.
Can I replace the heater control valve myself?
This is a great DIY project. It is low in difficulty, and very few tools are required. The novice DIYer should beware of hot engine coolant, and let the vehicle cool before attempting this repair.
If you're not familiar with the heating system, or aren't sure if the valve is the cause of the problem, it's best to leave this repair to a professional.
Heater Control Valve Replacement Cost Estimates
The average cost for a Heater Control Valve Replacement is between $559 and $629 but can vary from car to car.