The Klima relay is right next to the OVP relay by the brake booster. Typically they have KLIMA spelled out on them. It's one of those combination relays that controls the A/C compressor cycling and the trans kick down. Why the trans is lumped in there, who knows.

The transmission is very similar to the one in the 300SD. Same setup and same family. If the Bowden cable is set properly you should get upshifts when laying on the kick down button ~4600RPM. Normal upshifts will be somewhere around 4200RPM. 1-2 will usually be somewhere around 3000-3500 RPM, it should get out of the way pretty quick. The vacuum only modulates shift hardness. If the modulator is adjusted properly and the VCV is aligned correctly, you should get a quick/firm shift but not so firm that it jerks the car. If it's shifting smooth/softly, it's wrong. You should notice an upshift, but it shouldn't be unpleasantly rough.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

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