Heat doesn't work all the time

Some times the connector gets hot and causes poor contact at the resistor. Have your mechanic recheck it. Tell him you would like to come look at the connector when he has it apart. He should minimum check it for free.

Hi jkelley, I'm glad to help!

Usually in most cases when the heated seats quit working its the heated seat element that you sit on under the padding. Here's what I want you to do: Turn the key on then push the heated seat on button and see if it lights up. This is a quick test but not always an accurate test because the switch could still be working but the LED Light could be bad. BUT, in most cases this is a good test. If it lights up then its safe to say that its mostly likely the ELEMENT that's bad. Most of the time if you'll raise the seat cover you'll see that the element is burnt. Hope this helps and have an awesome day.

fuse failure or fuseable link wire/relay malfuntion.. check and repost findings..

If you are talking about the belt for the ac compressor, yes the heater should still work.
If the blower is not working, you will need to have the blower motor checked for voltage and ground.

Check the coolant level...if it's low the heater core in the car won't make heat.

Does the fan work?

GL,
Td

Is the fan blowing for the vents? If not the problem is a fan issue which is much more likely. The hot water usually goes through the heater core all the time and the only reason you get heat when called for is that air is directed across the fins and coils where your engine coolant is going through. Of course the heat does not come on until the engine has heat built up in it say after about 7 minutes of run time depending on ambient temperature.

Uncover it and see if it is hot if it does your fan or switch needs replacing if it's cold and the engine is hot. diconnect hoses when ciold and put them in bucket and have someone start car and put on rear heat if water flows flush out core or replace if it doesn't flow switch is not opening vale or valve bad. I would think there is no valve and there is hot water to the unit all the time. There my be a door that opens and closes like the front heating system

Could be the swap valve/damper not opening to allow air to flow thru heater core in rear or control switch not telling it to change.

I have a 2000 pontiac grand prix with a digital climate control system. The heat quit working, it doesn't blow out any heat. Now that it is warm outside the air stopped blowing out any air. The digital temperature on the climate control is not correct. When it states that it is below 30 degrees on the ext and it is warm outside the air wont be cold. Once it starts going above 30 degrees the air gets colder. Today the blower stop working all together. Was told it maybe the climate control unit was bad. You can hear the door opening/shutting when you switch the temp from cold to hot. But there was no heat blowing out whatsoever in the winter time. Could you please give me your opinion on whether or not it is the climate control unit or something else?

you might need a new cluster. try changing what is called the blower motor resistor. it's about 13 bucks. remove the plastic cover under the glove box and remove 2 bolts that hold it in. it's the only thing under there with wires. swap it out bolt it up and your done