I need to check the freon in my 94 SL500 r129 but cannot find the fitting. Help! on 1994 Mercedes-Benz SL500

Can someone tell me where it is located please?

Asked by for the 1994 Mercedes-Benz SL500
If it's "R12" then you need to take it in for a R134a conversion and then make the repairs that caused the R12 to leak out in the first place. No cheap fix here. GL