2006 Hyundai Tucson - A/C and Heater

Hi everyone, been having a problem with my A/C and heater: Neither are working! The Vent fan is blowing air strongly so that doesn’t seem to be the problem.

I first noticed the A/C wasn’t working. I replaced A/C compressor and the problem improved but there were still times when the A/C would stop completely. The cold weather hits and now I see that the heater isn’t working either!

Any ideas? Do these problems sound related to the same cause or have two things broken simultaneously?