A/C and heater are not working in the front?

My wife's car recently lost its A/C in the front as well as heating. The back works perfectly fine. I checked fuses and relays all seem to be ok. She does remember a slight knocking noise a few weeks back. I replaced the HVAC A/C Heater Blend Door Actuator (the one right behind the stereo lol) and still no luck. Any advice as to what steps to go through next?

Not sure if it has anything to do with this, but I know triple A recently replaced the car battery and within a month or so the brake lights, ABS, and the advantrac started to flash here and there very minimal. Now those lights are just solid. I went to AutoZone and they ran that check light device and they said there's no codes, to check my battery.