Can someone tell me if the dashboard sensor is used during heater operation or is it only used during air conditioner use? I have removed the air conditioning system and want to know if I can cover over the hole in the dash when I get the dash done over.

 

It's used for both. Without a signal from the sensor, the temp mixing setter will be either full cold or full hot.

 

Thank you much!

 

And if the (Outside) one in the right front fender is missing or bad the same thing will happen too.
You need both