99 ford explorer air conditioner not working

My air conditioning and heat won't work. We thought it was
the blower motor because it was working then it just
stopped one day and wouldn't push any air out. We
replaced the blower motor but it still wouldn't work, we then
replaced the resistor and still nothing. We have no replaced
the climate control unit in the dash that before would at
least turn on but now does nothing, the new and old one.
We are stuck what could be the problem. The compressor
works fine and we had charged the ac at the beginning of
the summer. My husband and I are unsure about what to do
now. I'm 6 months pregnant and have 2 other children and
can not afford to have a vehicle that doesn't have working
heat in the winter or ac in the summer.