i have a 1994 mercedes e320 sedan .my car just started doing this the other day.. randomly when i get in my car and start it the air recirculation switch light blinks really fast and i hear a clicking behind the dash along with it,.. it does this for about 2 minuites then stops.. once it stops sometimes the heater controls work and sometimes they dont .. can anyone help me figure out what is wrong and is this a common problem on my car.. im guessing there is a control box behind the dash that is tweaking out or something.. any help would be appreciated.. thankyou

In mine (with the pushbutton climate control unit) the recirc switch is mounted above the climate control in a row of more modern looking switches, and has a little red light which comes on when it is in use. I know that the switch has a timer which turns off recirc after a set number of minutes based on the outside temperature. It could be a malfunction of this. Does your car have the "rest" feature which circulates heat with the engine off for a while? A failure in this system could also cause the light, I believe. Essentially, the blinking light is warning of a CC malfunction. My first advice would be to disconnect the battery in the car for a 1/2 hour to an hour, or so, which will cause the electrics to reset themselves. It would not surprise me if the problem is fixed due to this. If that does nothing, than remove the wood dash piece which houses the Climate Control unit and the upper row of switches. All you have to do is unscrew the two phillips screws under the wood panel just above the radio and then GENTLY pull / pry the piece out. Behind it will be the CC unit which can be easily removed, as well as all the upper switches. Check for the obvious like shorting wires, breaks, etc...then take the black plastic cover off the CC unit itself and look at the circuit board to see if there are any melted or black spots out of the ordinary, or if something needs to be resoldered.
Hope this helps. I don't know if this is a common problem, but I have never heard of it.

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro

thanks for the info.. ill try the battery trick then if not .. take a look behind the covers..