Kind of sounds like the CCU is on its way out or needs resoldering work. The recirc button shouldn't have any tie-in with the monovalve or the Aux pump. Even if the Aux pump dies, you should still get heat. The failure to regulate temperature is a CCU fault. It should at least shut off the compressor and open the outside air flap at a bare minimum. Be aware that the push buttons themselves develop poor solder joints and can cause erratic behavior.

Funny story about GPS and St. Louis. I had pretty much the same thing happen to me 10 years ago in St. Louis with a Garmin. It told me to "Exit Right" into a maze of various exits clustered together, then "Keep Left", which I did. Problem was that keeping left put me on the wrong ramp and diverted me over the highway into a shockingly seedy looking area. I felt like the Griswolds after they took the wrong exit, quickly backtracked and got back on the highway!

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]