No heat
 

My 420SEL is not putting out any heat, no matter which setting the fan is on. I turned the temp control to max heat and nothing. Cool air only blows (outside temp is below freezing). Engine temp is normal. 80 degrees is reached in normal time and stays at 80 while driving, so I don't think it is the thermostat. Obvious first conclusion is the climate control buttons, any other ideas?

PS. Benzmac if you are there I replaced the OVP relay and my rough idle and stalling problems are cured. Thanks for the advice.

First thing is to replace the mono-valve insert. We have them and it is as easy as 4 screws to replace...It is located to the right of the battery.

Thanks again Benzmac - replaced monovalve insert this morning, quick easy and cheap and problem is fixed. Old insert was clearly defective upon inspection.

i just replaced my monovalue and then found that it didn't fix my problem so i have the old one. i would sell it to you for half price and send it to you if you want to pay the postage. it still works!

Thanks for the offer, but I think my problem is fixed. Maybe someone else needs one, you should try posting in the clasified section.