My my '99 E300 Turbodiesel EC light is constantly on when I turn the Climate Control on. I've been without heat, defrosters and AC, for about a year now. Probably why my brother sold me the car.
The blower comes on, but its like baby's breath, you can hardly feel it. Plus, I can't get that darn EC light to go out. Seems that the compressor dosen't come on with the EC light on.
So, I sent to a shop that a guy named "Joe Cool" works. He is an AC specialist. He worked previously with his father in a shop that did nothing but AC work.
I dropped the car off 5 days ago. The manager told me that the blower motor and blower motor regulator needs replacement at a cost of $ 907. After these parts are installed, they could look for other problems.
I really don't have that kind of money laying around, so if anyone can help this slightly disabled Navy vet, with a good set of hands, I would be much abliged.
Lou

 

The most common problem when the EC light is on is low refrigerant charge. Of course, the question is if it is low why? If there's a leak (likely) then recharging will not last long if at all.

Use the link below to run the built-in diagnostics yourself and see what readings you get. Post them here if you want advice.

http://www.eclassbenz.com/node/27

It's more common for the blower motor regulator to fail than the motor itself. At the very least, you could replace the regulator and see if that solves the problem.

 

for r/r blower or regulator on www.benzworld.org w210 forum or on
www.peachparts.com diy resource section.
You can test the blower and my suspicion is failed regulator
repair not much more than 100 bucks.
Then do as Richard stated run the onboard diagnostics.
900 bucks for a blower motor is highway robbery