1999 Alero Please help someone

It was 25 degrees this morning and my heat still does not work...I have bought brand new parts replaced the heater core, radiator, intake gasket,reservoir, and water pump. Realized this morning that when I turned the knob form cold to hot I did not hear it click over..A friend said something about my actuator could be unplugged? How do I know if it is unplugged or if I need to replace it...where is the plug?

Does the engine reach normal operating temp? Are the heater hoses hot? Does the blower motor work? The actuator is vacuum controlled, maybe a vacuum issue? You'll just have to look under the dash.

Does the engine reach normal operating temp? Are the heater hoses hot? Does the blower motor work? The actuator is vacuum controlled, maybe a vacuum issue? You'll just have to look under the dash.
yes engine does reach normal temperatures it usually goes up to the middle mark sometimes even creeps up a little past the middle line...I have to bleed it alot for the temperature to stay under the middle line... Sometimes my belts also stop for a few seconds...I do not know about the heater hose will have someone check...Oh forgot to mention just bought brand new blower also...Air conditioner blows just fine...Just whenever I turn the knob to hot the air coming out still blows really cold...

Your belts stop? Can you ellaborate on this?

What motor does your car have? 3.4 or 2.4?

If you have to keep bleeding it to maintain temperature you are getting air in the cooling system, most likely exhaust gases. I had this exact same issue, although I would get intermittent heat and then it would go cold, get hot, and so on.

Turned out to be a very mildly blown head gasket.

I'm sorry maybe it is my pulleys the belt looking things that you can see when looking down at your motor....Since the last time I emailed you I had to bleed it and the temp has not gone past the middle mark...is that where it is suppose to stay?Just need this car to last till beginning of next year then I can afford another one...lol...But what do you think about the heat...think maybe I should go ahead and buy a new actuator?oh and I have a 3.4 engine...Thanks for all the help

I'm sorry maybe it is my pulleys the belt looking things that you can see when looking down at your motor....Since the last time I emailed you I had to bleed it and the temp has not gone past the middle mark...is that where it is suppose to stay?Just need this car to last till beginning of next year then I can afford another one...lol...But what do you think about the heat...think maybe I should go ahead and buy a new actuator?oh and I have a 3.4 engine...Thanks for all the help

How often do you have to bleed the system, and do you know why? Are you losing coolant or what? An actuator could be an issue but there is a reason you are getting air in the system. It needs to be addressed.