My 87 F150 has had an issue with the intermittent wiper feature. When I rotate the wiper control towards the intermittent position, the wipers do not work intermittently but as regular wipers. It doesn't matter how I position the control in the intermittent region.I do hear the relay click as heard during intermittent operation. Otherwise the wipers work in the "normal" position both slow and fast.

 

I've never had the problem, but check out post number 15 at this thread. Could be cracked solder joints.
https://www.fullsizebronco.com/threa...t-type.136770/

 

When I had trouble with the intermittent setting on wipers in my '95, I used CRC Electronic Cleaner spray, liberally, in the rotating switch. And it fixed the issue. If your issue is in the switch itself, that could help.

 

You probably need a new interval governor raski
The diagnosis is such a beeaach, we used to just plug a good one in, and test it that way
If I find mine, I'll post a pic

 

Where is the interval governor module located on my 87 ? My FSM does a bad job when it comes to this item.

 

Not sure, but they used to be right behind the wiper switch because that harness connects to both the wiper switch and the factory harness
I can't find mine, but I am moving
If I find it, I will find this post and offer to send it to you