1999 F 250 7.3L wiper issues
 

The wipers work flawless on low and high speeds. On any variable speed they may work properly or they will move about 6 inches at intermittent times until it completes the cycle. I have read that it could be a relay or the multi function switch. Neither seems expensive but curious which I should try first. Thanks for any information.

Since pulse wiper system uses the low speed of the wiper motor and the low speed works fine, "Smart stick-Multi function sw" appears likely culprit.
The only problem is , it's a lot easier to replace a relay than the Multi-function sw. Tilt steering col ??

Yes....It has tilt steering column. My guess would be the multi function as well but would of been just that....A guess! Not afraid of replacing the Multi function on my own. Just making sure I wasn't missing something else. Thanks for the info. Will post after replacing the Multi function.

You may need some special tools (for tilt col) to get to the sw assy. Suggest you refresh the steps required before starting the job.

Will do! Thanks again for the info.....

Update! It is not the multifunction switch. Still have the same problem but it sure looks good. About a 20-25 minute job. What's next? Relay or actual wiper motor? Thinking of trying the relay first........

There are 2 relays involved with the wiper motor speeds. My reasoning suggests that once the motor gets going whether hi or low speed it will run.Relays are OK.

What may be happening is; the brushes in the wiper motor are getting to the worn out point and without sufficient pressure on the motor armature it may be enough to get the motor turning , but when power is interrupted as in delay/pulse, it is having a tough time getting going again. In which case,,,,,,,,,,replace the wiper motor assy. rebuilts are available.

Thanks for the info as always. I have done some testing with the relays and from what I can tell they are working as they should. As you mentioned the motor is probably the culprit. I will tackle this on one of my days off and it is a little warmer. Will update once I have done this.

Some time has passed and finally a fix. The wiper motor gears went out and the wipers stopped working all together. I replaced the motor with a new one from NAPA for about $90. This fixed the intermittent issue and wiper park problem. Works like brand new! As previously mentioned they only worked on hi/low and no intermittent/park. Hate that is took this long but hope it helps someone out in the future.

Sure is great to see a followup post on issues - and the final fix. Thanks.