I have a 420SEL with absolutely no heat. No heat on low, no heat on defrost, none! The monovalve was replaced and still no heat. Then, thinking it might be a bad monovalve, it was replaced again and poof - there was heat, well for a few minutes. I tried to turn the heat down and now I am back to no heat.

Suggestions? Heater control panel? Difficult to change out?

I would certainly appreciate any and all advice.

After three bad ones in a row, I stopped buying MTC brand "monovalve repair kits" from a well know online parts supplier in Arizona. Since, I have salvaged monovalve units from yards and found they do work.

I hope this helps,

__________________
Will



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