Idk if it’s a sensor or a switch but it’s mounted in the evaporator. I have a 93 Honda civic with the r12 unit but going to be replacing it with the r134 unit.. The only difference is that the r134 came with the 3 pin plug type (evaporator thermostat) and the r12 came with 2 pin type. I was just wondering if can just switch out the r134 sensor with an r12 sensor and if it would make any difference??