1999 chevy malibu the heat doesn't work. The fan keep on blowing cold air.

SOURCE: My 1999 Ford F150 Heater only blows out cold air

guys have you checked for a vaccum leak????? there is a little plastic ball with a vaccum line going to it that controls the outside air coming in. check for a leak in this line

SOURCE: 1999 chevy malibu engine keeps over heating,

Overheating could be a combo of many thing's.If your thermostat is stuck you will have no circulation which will cause overheating.Also if your eng. has alot of miles your water pump may be in need of replacement.Listen for your radiator fan motor and be sure that's working and also check to see if you radiator is good.If your loosing antifreeze because of a headgasket you will see a white cloud out of the exhuast because it is burning it and sometimes you also get a little in your eng.oil.Using a pressure tester on your coolant system will help to diognos the problem,if you have a leak some where it will not hold pressure.Sign,s of a bad waterpump are poor circulation and a antifreeze leak from a vent on the waterpump.Be sure the eng. is cool before working on it.Hope this was helpfull.

SOURCE: 1999 Chevy Cavalier A/C blows hot air

More likely the recharge blew a o-ring and you have a leak. When your Cavalier was blowing hot air and a recharge fixed it that means it was low on freon which lets o-rings dry out, go back to the shop and have them leak test it. They use a pressurized dye to find the problem. If it's blowing it's not the cooling fan relay, they may have meant compressor relay but I'd have a leak test done first it's not expensive and easier that chasing unknown possibilities.

SOURCE: Rear a/c not blowing cold, front works fine.

you may not have enough refrigerant. a low charge can cause the rear in this dual system to not work for beans. charge with a can of uv and find the leak. fix the leak. evac the system and recharge. i think you take 4 lbs, but check the accumulator sticker. you may want to just change the accum at the same time.

SOURCE: 1997 buick lesabre HEATER PROBLEMS The fan

This could be several things. First I would check that the thermostat is not stuck open. This will condition will make the car run cold when it is cold outside.

If this is not the case........and I'm assuming you've already checked that the antifreeze is full, make sure that the heater valve is working. If it is frozen in place then it won't move and won't allow the warm water to circulate through the heater core.

I'm basing my answers on a standard Lesabre. Yours may not have the standard climate control.