Mercedes: 1980 450SL Mercedes Benz 107, 450sl mercedes, mercedes benz

Question
The air will blow, but no heat whatsoever! It would be nice if the air that blows over the engine when heated up would even blow inside the car. Just anything or quick fix is good for me, as ten degrees is a bit cold for me to ride around in! OUCH
Thanks

Answer
Hello Brent.
I would suspect that the 'mono valve' is not getting the electrical voltage needed, or that the valve plunger is stuck. I had an identical issue with my 86 420sel. On my car, the mono-valve is located inside the firewall pocket. It has electrical connections on the top with multiple hoses exiting the valve.
Mercedes wanted 300.00 for the valve, and aftermarket web site wanted 175.00. I went to Ebay, my favorite place for used parts, and purchased an OEM new unit for 10.00.
When it came time to replace, I decided that there was a good chance I would break some of the hoses to get it out. I opted to just remove the screws in the top and pull out the internal part.
I separated the new plunger and solenoid and dropped into the old casing, replaced the screws and have had heat ever sense. I could probably have cleaned the gunk of the plunger and it would have worked, but decided that the new unit was the way to go.

Having said all this, I locate additional information at this site.

http://www.justanswer.com/questions/1nhmj-i-have-a-1980-450sl-that-the-a-c-is-bl...

Good Luck
Rob