Got this Mercedes with a problem in the recirculation switch circuit. Seems this little button is tied into a whole lot. In pulling the wiring diagram one will realize the far reaching roots of this little switch.

The red light will come on and off, and also cause some clicking now and again. We originally just disconnected it after this condition arose after being wired for a remote start and alarm/stereo system at Mickey Shorr. Now with the warm weather it seems to have an effect on the engagement of the AC compressor also. While the AC system is holding 134a with no leaks, and upon manual engagement of the AC compressor it blows nice and cold, the problem is now going to require a throughout inspection and testing of this circuit.

Just wondering if anyone else has had a Reregulating air switch gremlins? For the people whom dont know what this is, its the switch on the top portion of the center console, just above the climate controls with several arrows pointing in a circle. This switch makes the air box reuse the air from inside the cabin, so that it does not draw air from the outside, making the heating and or AC cores work a little less.