Stick your head under the hood. If the AC compressor is missing, then likely also the wiring that also controls the fan etc. Likewise, check the heater hoses still go to the firewall ports which lead to the heater core in the heater box under the dash. Often these are disconnected and plugged up, or bypassed once the heater core fails and starts to leak as its a big job to fix. Other than those basic checks, could be many things to fix.
