I've been reading all these post and my what complications of the heating and a/c units of these MB's. Well in the winter my heater wouldn't work until i drove it about 20 miles. It starts a clicking noise under the dash on the passenger side. Does this for about 5 min. then MAYBE my heater will come on. Now that Spring has arrived and I use my A/C some. The A/C works fine, but when i get out of the drive the clicking starts up again and does it for about 5 min. Is this the climate control that's making this noise? Where is it located exactly? What is the cost in repairing at a local MB shop?