Chevrolet Repair: 1997 Chevy Tahoe Wipers, chevy tahoe, rain storm

Question
I have a 1997 Chevy Tahoe 4X4 that has wiper problems. They may work ok for several months and then when I try to use them they may work for a few wipes and then stop and then after maybe a minute or so they start working again and may quit again. Sometimes when they are working I turn them to the off position and they keep on wiping. I put them in the intermeidate position and they wipe as if they are in the low position and wipe all the time. Just the other day I was in a hard rain storm and as I was driving down the road they quit and just as I got off the roadway they started working again. I put them in the fastest intermediate position and they wiped all the time not stoping. I then put them in the off position and they kept on wiping for a couple of minutes and finally stoped. This may not happen again for a couple of months and then again it may happen today. Have been to several repair shops and have been told by all that unless they mess up when they are checking them out there is nothing that they can do. Surely there is a starting point to check out this problem. Any ideas as to what the problem is or where I should start looking?  Thanks, and have a great day.

Answer
There is really only three places to check. The switch itself, the plug at the motor and then the motor itself. The two most common places is the switch or the plug. Easiest way is to have them running and then jiggle the plug at the motor pretty good(push in, pull out, side to side and up and down) if they don't mess up then I would say the switch may be going bad. Usually if the motor is going out it just goes out.