Can somebody tell me how to activate the window-wipers for PMDG Boeing 737 NG. I tried the two switches on the overhead panel but they don't work. Thank you in advance. Regards

They are not functional on the PMDG bird. They are only there for asthetic purposes.Sean

Actually the window wipers are functional on the pmdg 737 (only in the 3d cockpit though, and they don't actually wipe the rain water off the screen)