I have a 2001 f150 and have no heat. I can turn switch to off and wait about 4 minutes and turn it on and it will blow warm air for 2 minutes then cold, wait and repeat the process. I pulled the dash today and got the top off the heater box and the blend door will not move. I am trying to get the blend door motor out. should you be able to push the blend door closed to the evaporator? The Motor is a pain to get to to un bolt. not enough clearance to the the vent under it out. What is my next thing to check out?

Thanks in advance
Larry

 

I would definetly put a new heater core in it, since it's already apart.

 

In for info, ive had the same issue it no heat for the last two years in my 01 screw. In my case, I know the blend door works at least sme as when switching from cold to hot it can be heard and does change the temp just a hair but I oly get Luke wam air. The core has been flushed twice, each time get some crap out and it works a little better for a few days then back to luke warm.( almost like a clog that is too stuck to remove.) I'm sure I'll be doing what you are doing soon. Good luck Larry.

 

Mine was pretty much the same for the last month then suddenly this week the heater core went out. That doesn't mean that yours will do the same or that the issues are related. I would do some further investigation into the heater core while you have the dash apart though.