i have been working on mercedes cars for many years, but even this one has me stumped. at times on my euro 500SEL, when making a hard left turn, like whan taking an offramp that goes at a left turn angle, the heater will come on and let out full heat. so high you have to lower the windows, i was suspecting the mono valve, but havent pulled it yet, has any one seen this type of issue before? any help would be appreciated.