Ok here we go. I have a 1998 C280, last week I had the AC filled with freon as it was low. Obviously, there is a small leak. A week later the economy light came on and hasn't gone off. I have been told that it's either the evap sensor or reg. temp. sensor. I bought them from the dealer today. Tomorrow I will replace them. My question is, am I barking up the wrong tree? Also, how much freon is supposed to be in the system? Any input would be greatly appreciated, more than you know.

Thanks,
FA