300E thermostat, and some side issues

As usual, I turn here for advice. You people are a valuable resource. I may need to replace a thermostat on an '89 300E. The only book I have shows only a four-cylinder engine. Is the thermostat on the top heater hose, just forward of the air cleaner? This looks like a very simple job. Simply remove and replace after draining the coolant. Please tell me if this is correct.
On another issue, my cruise control has never worked since I bought the car used. At least the control lever has gone south, and I was about to replace it, until reading your advice to someone with another MB model. Does replacement of the lever on my car require removal of the steering wheel as well? I do appreciate having your Shop Forum as a place to learn from other people's experiences, Thank-you.

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