I am going thru all the fuses on the '86. The wipers are not getting any power however everything else works.
I cleaned all the fuse connections and double checked the fuses for possible broken filaments. So far so good.
When replacing the fuses I noticed something odd. The Main fuse box #9 is for the Wipers. The Owners Manual and the guide on the inside of the access panel both list this as a 35Amp fuse however the paper strip in the fuse box says 20Amp. All other fuse Amp positions align between the three, i.e. Owners manual, access panel and fuse box paper strip guide. Why the difference? 35Amp is the way to go I presume.

 

The S57 shows two fuses for the wipers.

#9 is 20amp
#11 is 35 amp

I've seen some discrepancies like this before. When in doubt I go with the lower rating and see what happens.

Cheers
DD

 

35A seems very high for a wiper motor...

 

I think the 1986 cars still had the cable driven wiper arrangement.
Many places for that system to lock up, plus those motors fail with burned bearings or worn brushes.
That old a motor can also loose internal magnets where the epoxy fails.
First thing I would do is disconnect the motor from the wiper mechanism.
If the motor runs fine then you have a mechanical issue down the line.

 

This car has the same wiper motor setup as in 87-91 cars. The motor mounted to the grill with a large 8 pin plug on the passenger side. The motor is good, it has been tested. The issue has been no power at the plug .... or on the fuse terminals. Everything else has power.