I have a 1999 e320 4matic and the air and blower only come on when it is cool out. If it is really hot I get nothing. Sometimes when I am on the highway going abot 60 plus mph, it will pop on. I t is the same with the heat. Once in a shile I will be driving and it seems if I hit a bump it comes on also. It will never come on when it is hot outside and that is when I need it. Please help

 

Replace the blower motor or the speed controller for the blower, more than likely it's the blower motor

[IMG]local://upfiles/5782/8C9602BFB4FB4B77B0CD6ABE032E46D9.jpg[/IMG]

 

i'm havin' the same prob on my 2000 s430... hopefully that's the right solution...

 

I had a similar problem with my 99 C230. Dealer wanted $1800 for a new compressor. A local Precision Tunemechanic found aloose wire going to the compressor.