This was to fix my 1988 convertible wiper switch that was hopeless.
To remove the switch assembly you need remove the upper and lower switch covers.
Note the screws for the switch covers are a menace. Check this post to buy sensible screws and save frustration: Switch cover screw problem.
It helps to remove the steering wheel first, and maybe the big left and right trim pieces around the instrument panel to free the covers.
Remove the big cover panel under the steering column.
The wiring harness for the switch has a moulded Lucas 8 pin plug/socket and I could not get my hands up and under the cross tube to free it. They are mighty tight to separate.
Hence I cut the harness so I could lower the plug/socket slightly and after a 15 minute struggle with pliers and vicegrip managed to pull them apart. That was a nuisance but did pay off in that I had bare ended wires to the switch and I could easily check its operation once it was repaired. There are also a couple of black wires to free up.

Next you need remove the press-on fix holding the plastic pivot pin of the wiper switch. It needs great care and that was 20 minutes of work. I actually had 2 press-on fixes in that place, bit of an overkill or a factory accident. To remove the switch from its bracket you undo 2 screws - the easy part. You can drill and file the rivet heads off the switch. In fact rather than rivets they are peened over pillars which are part of the diecast switch body.
You need avoid the whole thing springing apart as you finish dealing with the rivets. You can use a rubber band or cable tie to hold the two halves together. When ready to separate it is best to hold it in a deep dish so you can catch the springs and other items. The photos show the detail.

I cleaned up the wedge shaped plastic cam and copper contacts, then superglued the contacts in place. The cam moves up and down in a slot and completes circuits by shorting out the mating contacts crimped on the harness wires. There is a piece of insulating material which fits in the plastic body next to the cam slot. It has a notch which allows the switch stalk to pivot and give a wiper flick.
I applied electrical grease to the cam and contacts, the springs and ball bearing, and the 4 detent grooves in the plastic body.
To make sure all was correct up to this point I moved the cam in and out of its slot and used a multimeter to make sure the harness wires that shorted agreed with the switch wiring diagram.
Luckily the wiring diagram was done by somebody who really knows their job, it does make sense.

The way to reassemble the whole shooting match had me puzzled at first,
Meaning how to hold the spring loaded cam in place, plus the detent spring and button, while fitting the plastic body back into the diecast body.
Luckily if you push the cam down as far as it will go, there is a place on the plastic body where you are able to drill a 2mm hole and then push into the hole a 2mm drill bit. That drill bit will hold the cam down while you fit everything in place.
See photo for location of drilled hole. Once that was done I held the 2 halves with a cable tie.
Once again I checked the harness wires shorting against the wiring diagram for all cam positions.
To hold the 2 halves together permanently I used a contact adhesive for drywall cladding. I put as much as possible in place and let it harden for 2 days. Then removed the cable tie and applied more in the resultant gap. So far I have put the switch back and it works fine.

One issue is that the generous greasing of the switch components means the cam spring can almost overcome the detent spring pressure holding the stalk in the “OFF” position, it is hair trigger.
I am not sure if it was designed this way, but I get the flick action by pivoting the stalk in the OFF position and also if I drop the stalk to the 4th detent position.
When I put the switch back on its bracket I did not bother with the press on fix, it does not seem essential.
I used terminal blocks to rejig the harness. To make sure they fit in the available space use 2 small separate ones.


Cable tie first before de-rivetting.


Switch parts


Copper contacts superglued in place


Other side of the cam


Stalk and detent, add spring and button


The correct hole to drill is the lower one, that is to hold the cam down





Cam held down with drill bit. Note notch position on adjacent piece


Switch fixed and ready to go

 

Very useful and very well illustrated and clear writeup. Thanks indeed!