uniccojoe@yahoo.com

I have a 1999 f150 that is having ac issues. I had the system recharged, the compressor replaced and a few other things..... but I my ac still does not work correctly- it only works on max ac with the fan on high. Even then it only works for a while less then an hr. If I turn down the fan speed or turn the ac down to normal it blows hot air........... any ideas???

Thanks

mike61

you could have a bad blend door in evap case? if you can put a shut off valve in line in one of the heater hoses. check vaccum lines to blend door, should be able to see it if you remove glove box? do all the fan speeds work? if so i think the blend door maybe your problem. the blend door is what switches between heat and a/c it has some foam on it that is supposed to seal out the heat from air being drawn across the heat core or the evap . the blend door can be replaced but you have to remove the evap box from behind the dash! the shut off valve will help to stop the hot water from flowing through the heater core and give the evap core a better chance to let all the cooler air out
hope this helps