w140 climate control issue
 

Please excuse me if this has already been covered...I have a 1992 400se , when either in economy mode or with the a/c on the 2 side dash vents will suddenly start to blow out the hottest air you can imagine. Its not all the time ,not when you first start up ,not even in traffic. I can be on the highway and the temp guage is in the lower half and it just does it. It does go away and then comes back again.
any ideas?

WELCOME!
Here are a couple of word groups you can use in search feature here on the forum and read through the threads to see what others have done.
"mono valve"
"re-solder CCU"
"ACC Programer"