1999 ford explorer..no air at all.i leave the air on even though its no blowing.and sometimes it comes on..when it does.everything seems to work fine.then when i turn car off..doesent come back on

your air conditioning requires a certain level of charge for the compressor to become activated, when the compressor runs accumulates a charge and this is disbursed throught the evaporator what does the cooling and the condensor which gets cooled at the radiator...is a tenuous balance and when you shut the engine off, and charge remains, the compressor will not switch on until the charge that is holding balances out....then will engage normally...if performance is slow would take it to an air conditioning specialist who will change out the filter/drier and recharge with the correct refrigerant~

Do you mean that the HVAC blower does not work? If so, it probably has short brushes and it needs replacement. If it moves air all the time but it's not always cold, have the system charged as the Judge suggests.

even the heat last winter would only come on occasionally last winter.and now the air cond only comes on every now and then..but when it does..its very cold.i thought that it might be the blend door..so i cut a square out behind the glove box..and kinda played with the door.with the air on and truck running..and the air cond came on. but when turn truck off it wouldnt come back on unless i messed with the door again..i did this several times.now..i cant get it to come back on at all for some reason.i can feel cold air when i put my hand where the blend door is.sometimes i could hit the bottom of the box under the glove box and the air would come on..and has worked for several days,,but not now ...and thanks for your help..