Hi,

On my '88 F150 the delay operation does not work, when i turn the switch to left the wipers run as on first speed.

THe other problem: no matter what position the switch is on, after few minutes of operation the wipers begin to stop occasionally for a second or two in the middle of the screen.

what might be the prob here, maybe the wiper switch?

 

I had this problem and found out it was the wiper motor.I have a good switch and motor if you need them for 3 (yes three,not here to make money but 3 bucks will make me feel better about storing them for past 2 years.)bucks apiece plus shipping.Goodluck.