The slow speed has never worked on my 69's windshied wipers, but last week the whole system went out (or won't stop). When i turn the switch off the motor won't quit. I got out the test light and found that the center wire is hot all the time. When i disconnected it the motor stopped. I also found that there was no power going to the wiper switch even though the fuse was not blown. I have no idea what is correct or not so hopefully yall can help me out. Thanks.

sounds like a bad ground..
the wipers are always hot and the switch is the grounding point.. this completes the circut..

Think the 69's and 72's are the same. Had the same problem with my park style 72. Problem looked like the switch not opening the ground line. I checked the ground leads to the motor connector. They opened and closed as I hit the switch. Problem turned out to be the park circuit inside the wiper motor. Put a rebuilt motor in there and all was well.