Where are A/C measurement points-190E
 

I have spare R12 and a gauge set. No A/C this year, worked fine last summer. No previous experience working on A/C of wife's 1993 190E. First step to take measurements but I can only find one hose point, near top of shock tower, drivers side. Where is the other hose fitting?

With high side gauge attached to the one fitting, pressure goes down nicely when I start the engine, and a/c compressor clutch kicks in, but without seeing the other side I don't know all there is to know.

From doing a search, I see to also check the monovalve, fuses, and vacuum hoses.

Thanks for any replies.