Grease Monkey
Grease Monkey

Fix heater not working in Ford F-150


America’s most loved truck, the Ford F-150 also faces one of the most annoying issues. The Ford F-150 heater not working / F-150 heater malfunctioning is a common problem faced among many ford model years. 

Model years facing heater issues: 

The F150 models starting from early 1993 till recent years share heater malfunctioning problems. Specifically, the model years:

  • 1993-95
  • 1997-03
  • 2005-07
  • 2010-17

All of which show heater issues mainly after 130K-150K miles.

Fix heater not working in Ford F-150-3a67 #1-

Cause: What causes Ford F150 heater to malfunction?

There are many possible causes for the F-150 heater to malfunction. However, it happens mainly due to three reasons. 

Low Coolant level:

The coolant is mainly responsible for regulating engine heat. But it serves many purposes. One of which is carrying engine heat to the heater core where heat is exchanged. This way the coolant gets cooled down while the heater core heats up. Air is then passed over the hot heater core, getting you warm air. 

Having a low coolant level not only means that your engine is overheating but your heater core is also not heating enough to blow hot air. 

Failing Heater core:

Heater cores also fail or deteriorate over time. While they are built to last a long time, generally 10-15 years, simple clogging can render them useless. Over time you can expect them to leak, which might also cause low coolant levels. 

When facing a leak, you can expect symptoms like a unique sweet smell in your cabin, wet floorboard on the passenger side, or condensation to form on your windows despite the defroster, all due to leaking coolant. 

A clogged heater core on the other hand would force the engine to overheat as the coolant won't be regulated properly.   

Malfunctioning Thermostat:

Thermostat regulates engine temp by isolating it from the radiator. It allows the engine to perfectly warm up after which the coolant flows through so the engine doesn’t overheat. In case the thermostat fails, the engine temp stays at low failing the heater as no heat is transferred to the heater core.  

Related causes: 

Apart from these, you can also have a faulty heater simply due to a loose coolant hose. Any hose or pipe connected to the heater core might be loose or leak causing it to malfunction. A faulty water pump can do the same with the heater core. 

Solution: How to fix the Ford F150 Heater not working? 

Fix 1: Refill Coolant/Antifreeze 

Among many cases of malfunctioning F-150 heaters, low coolant level has been found to be the most common reason. Refilling should solve the heater problem. 

However, the type of antifreeze you use depends upon your truck model year. Taking a quick look at the user manual can get your better insight.  


Ford Trucks before 2002: Motorcraft Premium Antifreeze (IAT), Green color.

Ford Trucks between 2002-10: Motorcraft Gold Antifreeze(HOAT), Yellow color.

Ford Trucks from 2011: Motorcraft Orange Antifreeze(OAT), Orange color.

How-To refill the Antifreeze:

  1. Start by popping the hood and locating the antifreeze reservoir (semi-transparent white container with green/orange/yellow fluid inside ). 
  2. Then, open the lid and refill the coolant. 
  3. Now start the truck and let it idle for about 5-minutes before running the heater again to see if it's fixed.

If the problem arises again due to the same cause, make sure to check for coolant leaks. 

Fix 2: Replace Blend Air door Actuator

With the F150 heater malfunctioning, it is often seen that only one part of the car fails to blow hot air. That is caused due to a bad blend air door actuator which in a Ford F-150 is located behind the center console.  

Replacing which can run you between $50 -$500 for F150 depending on where it's done. The actuator itself cost around $50 which can be replaced with the help of a screwdriver, wrench, and a bit of patience. 

To replace the blend air door actuator, you would have to remove the lower side panel of your F-150 center console, reach in and unscrew the older one, and finally, replace it with a new one. 

The video below would help you perform these steps better. 

By using these two fixes you can stop the F-150 heater from malfunctioning, making your commute a lot warmer. If these fixes don't seem to solve your problem, consider getting your heater core checked.