canon a-1 shutter release problem

I have tried to search the forum for help to my specific problem, but
I haven't found one that works yet. I am hoping someone can help.

I have a Canon A-1 that has an inoperative shutter release. I can see
changes in meter readings in the viewfinder, though in order to see
them, I must first (and every time) move the multiole exposure tab to
the left and reset the film advance (or it won't advance). I get no
battery check light, even though I am using a brand new battery that
works perfectly on my other A-1.

Any suggestions would be greatly appreciated!