wipers only work on high, wont park
 

Good day: Please give some advice. My wipers work only on the high setting and wont park. I replaced the control stick with a used part, but this didn't solve the problem, still works only on high and wont park.

Also, the cruise control didn't work at all, but when I took out the old cruise control stick, it came apart, and a small metal ball fell out. I put it back together but I couldn't figure out where the little ball came from, so I left it out. Now, the cruise sometimes actually maintains speed, but its iffy because the stick flops around, and sometimes it just wants to accelerate without stopping until I flip it off. If I knew where the ball came from, I could take it apart again and put it back together right, since now at least I know the problem with the cruise is in the switch.

Do you think I got another bad part and the wiper problem is in the wiper motor? Or should I try to replace the stalk again with another one?

Its a 1981 300D with 350,000 kms. I've never done more than add gas and oil to a car before this.

Thanks, Kevin