morn all having a problem on my 70,wipers run all the time until the key is turned off.i tried an external ground wire from motor to firewall still the same.tried another switch also to no avail.motor speeds are ok,just wont turn off with the switch. thx mark.

Hidden wipers? What happens if you pull the connector off the motor. Next jumper from the alternator large terminal to the motor terminal where the yellow wire goes to. (Be sure of the terminal.) Does the motor run by itself?