1997 Explorer heater problems.

Ok so I have a puzzle on my hands, my heater in my explorer is not working! I have changed the thermostat, fluched the heater core and checked the blended door. When I turn on the heat air blows out of the vents like it should but its not hot. The car warms up like it should, and today it did get a little warm while I was driving down the road but as soon as I stopped at a red light it went back to being cold again. Does anyone know what could be going on that would cause this?? Your help is greatly appericated!

Welcome to this forum! I've moved your thread into the A/C & heater section. Check the coolant level. It might be low. A vacuum leak or a bad blend door actuator could create similar problems.

Thanks so much, The coolant levels seem to be where they should, the blend door is working properly, how would I check the vaccume leak and where would I start looking? Thanks!

Check the heater control valve.

Same issue

Where would the heater control valve be located? I have same issue with the heater and A/C. I have checked the blend door, the actuater, the the fluid level and found no issues.

Welcome to this forum! Follow the heater hoses. You will see the valve near the heater core on the passenger's side under the hood.

Well I found the heater control valve. It was located on the front of the engine on the passenger side. Now the next step how do you check to see if it is operating or not. I have tried various settings on the controls but I did not see the little arm move. I just want to make sure it is broke before I spend time and effort replacing it.

I'm having the same problem as you warm but not hot air... Blower motor blows fine, coolant full, blend door works.
I checked my heater control valve and that also seems fine.

To check it, depress the middle of it (the rubber top) with the engine running and warm.. if you reach your other hand in the passenger window and feel the air blowing, the air should cool off as you depress the valve (you are stopping coolant from flowing in the core) Release and you should feel the air warm up again.

If I turn the temperature selector to cold the temperature doesn't change so I'm thinking the problem is the control knob (heater blend door actuator to be precise)

Well I checked mine today by turning the control to A/C MAX and it cycled the arm to full closed. At any other normal setting the arm stays at the same location (full open). The question I have now is "Does the valve just go fully open/fully closed or does it partically close depending on when the temperature control is set?"

Tomorrow I plan on marking the location of the arm and see if it moves at different temperature settings. Since it does function I know I don't have a vacuum leak in the line. I will let you know what I find out.

Well I checked it out the arm it is only fully open or fully closed. Fully closed on MAX A/C and full open at any other setting. At the same time I flushed the system out but that did not help any. I also rechecked the mixing door actuator and that does cycle the way it should. Also rechecked the mixing door pin and that is not broke. Next thing I will check is the temp control inside.

Well I just figured out what my issue was. The blend door was stuck. I read some threads where they said the door got stuck. I hit the casing with my dead blow hammer and all of sudden I had heat that I could regulate.

It is strange that it did not break either the actuator or blend door pin but I sure glad it didn't

Thanks for the update!

First post

Joined due to this problem.

Excellent thread. It appears a lot of Exp owners have it.


I will try banging. If that doesnt work ill cut a hole in it.