A/C on off button, circuit board fix

Okay, I put in an after market double din pioneer I had in this car the only problem is the circuit board behind stereo broke and it's all one piece including the A/C on and off button that has to be pressed on for A/C to get cold and compressor to come on. I was thinking of somehow wiring a toggle switch, but what exactly is the correct term for what the button controls? Any cheap ideas on how to fix this without having to buy a entire new piece?I'm referring to the A/C button next to the recirculate and defrost button.