2 problems with 85 300SD

[yuke]

1st problem is intermittent wiper does not work,low and high speed work but when I shut it off it stops wherever arm is at the time I have to time it just right to get it to stop at bottom of windshield.Last time I had this problem I replaced relay #000 821 08 63 with a used one it worked for awhile and now same thing again. I was wondering if there is some way I can put power to the relay to check it if good or not or should I try to check the stalk out to see if problem lies there? Also in this snowy wet weather my floor boards on both passenger and driver side in rear are soaking wet any ideas where this water could be coming in at?