Olds Silhouette Passenger Side wiper not working

Either the wiper arms are loose or stripped on the pivots or the wiper linkage is broken. Try tightening the arm to pivot bolt. If that doesn't work, remove the plastic cowling and examine the linkage. You can buy new linkage for it.

bad windshield gasket.you could take it to youre mechanic and have it replaced .

Yes, you did.

there is 2 wiper motors . 1 for the drivres side and the other for the passenger. sounds like a bad passenger side motor

I had the same problem with my 2001 Mercury Marquis, but it wasn't the heater core, it was the compartment for the condensate drain for the air conditioning and the compartment to catch the rain water that comes down the windshield and drains through the windshield wiper cowling. You have to take off windshield wiper on passenger side and cowling underneath the wiper of the passenger side and you will see a screen over in the corner and that's where the box is for the drain. so much trash was down in there that the flapper wouldn't open to let the water out. Ours only leaked when it rained, but it looked like it could have been the heater core. Good luck.

you maybe right. check the air vents outside of the vehicle under the windshield wipers, also check the rubber seals around the passenger door, and window.

when the wipers are off make sure the driver and passenger wipers are at same level on windshield
you can adjust them so they don't go off the edge or hit the bottom.
if they are hitting off the edge and hitting the bottom as well you need to check the linkage since it may be worn out.

It is underneath the black plastic pieces under/below the wipers. There are just a few round fasteners that hold down the passenger side piece that need to be removed to access the filter.
You have to remove the windshield wiper arms, then take off the plastic molding that lies between your windshield. Once that is off (it comes out in two pieces) on the passenger side of the car, under the windshield just behind the firewall there is a plastic rain shield with two screws. Remove the rain shield. The cabin filter is under that rain shield. FYI...every bolt is metric, and be careful when removing the plastic molding-only turn those screws a half turn, they break very easily!

the wiper arm assembly is stripped for the knurled knob that is sits on.  replace the wiper arm with a new one.

Yes the spring in the arm is weak, replace the arm and your problem will be solved.