Flickering AC switch seems to be a huge problem with Mazdas. So my question is, why not bypass the factory AC switch? I figure a well placed rocker switch running thru a relay direct to the AC compressor. I know the problem is not the resistor, fan motor or state of charge with AC system because when it does work, gets really cold. This is a 2002 DX that I have had since new. I have tried new switches, crimping connectors ect. Fix sounds simple but am I missing something? Have not been able to find a schematic for the fan switch to confirm my idea.

 

You can't run the compressor full-time, it needs to cycle on & off to maintain a set pressure, otherwise the pressure goes too high and goes BANG, psssshhhhhh.

 

Ok, a grenading compressor would be very good. Plan B. Compressor runs off a relay in the relay/fuse box which I am assuming is triggered by the AC button. I could figure out which wire is the "signal" wire from the AC switch, which wire is constant power to the relay and which wire powers up the compressor. From there, my relay could/would trigger the OEM relay, effectively removing the AC load totally from the blower fan switch while keeping the OEM relays functionality. Geez, wish I could find a schematic of the HVAC controls.

 

Seems like a lot of work when you could just replace the switch?

 

Except that it's not just the switch. The A/C button on the dash is actually not the switch but a button that pushes the micro-switch built into the A/C / Heater control modules circuit board and it isn't serviceable. Wonderful design.