2000 Bravada Heater doesn't work

In May I had the air conditioner replaced and didn't think to check the heater when picking up the car. Today I noticed the heater doesn't work. The output is fine, but the temperature is cold. Can this be related? Any suggestions? I really don't want to pay another $800.00 Thanks!

Your heater core needs to be cleaned out or the blending door is jammed or broken.

$800 for air conditioning.....??!!

Don't go back to that shop at all. They are screwing you.

Man I just don't know how anybody can rip people off and sleep at night. I guess that is why I sleep so good after being in the business for over 25 years.