i have a 99 f350 7.3 psd 4x4. i leave in miami FL it rains here almost everyday when i am driving in the rain and turn the wipers on the truck turns off. turn the wiper off truck turns on. i have to be with a bottle of rain-x on me at all times. can someone help me with this problem

 

Some of the 99's were known to have windshield leaks. Not big ones, but a small amount of water that would drip on the back of your fuse panel where you can't see it. I'd take the fuse panel under the dash out (4 screws), and look at the back side for any signs of moisture there.

 

Check the following threads..
https://www.ford-trucks.com/forums/1...tting-off.html
https://www.ford-trucks.com/forums/6...out-issue.html

 

My wife's 2000 expedition had a similar problem after having the windshield replaced and that is what it was, it wasn't sealed properly and the fuse panel would get wet.

 

i have checked for moister and leaks it's all dry.

 

Have you changed the cps?

 

changed the cps 1 year ago with ane from ford.

 

You may want to check the output of the alternator ....

 

Just thinking out loud, did you pull the steering column plastic panels and look in there for a short or something like that? Windshield wiper and the ignition are opposite of one another on the column. Just a SWAG.