Wipers work and park, but rest at A-pillar between cycles - 94 Ford

[kishy]

Hi friends,
As I continue fighting my way through making my 1994 Crown Vic be ready for its safety inspection, I've arrived at a bizarre problem. I have searched but if this has been posted about before, I do not know the words that were used to describe it at the time.

By all conceivable metrics, the windshield wipers work. However, when they pause in between wipe cycles, they rest at the A-pillar instead of just above the hood. The wipers park correctly when turned off.

I went at this kind of blindly, despite having the shop manual and EVTM, I didn't open them at all for this.
I disassembled everything to get the motor out (what a pain compared to a box). I poked around with what I am going to describe as the reversing switch, the black plastic component that is mounted on the lid of the gear housing. All I was able to do by manipulating it was break the parking function entirely.

I have now picked up the following items from the junkyard:
One 1993 Town Car wiper motor. Application list for this part is 92-94 Ford/Mercury and 90-94 Lincoln.
One 1988 Vic reversing switch. It appears to be the same despite the motor varying.
One 1991 Vic reversing switch. Ditto as above.

I have now done the following:

1. Connected the 93 LTC complete motor. It does not operate at all.
2. Installed one of the junkyard reversing switches on my original motor. This worked identically to how the car was before I monkeyed with it at all (e.g. restored park function but still pauses at pillar)
3. Swapped that out for the other junkyard reversing switch, again on my original motor. This worked 100% correctly for about 10 wipe cycles, but then the wipers shuddered (started/stopped several times in one pass) and then began pausing at the pillar instead of the hood.
4. Swapped that out for the reversing switch off the dead junkyard motor. This once again worked identically to how the car was before I started.

So, having not looked at a manual at all, but having parts-cannoned it somewhat, and having observed it working properly for a short time, it appears to me that the problem is with the reversing switch. Or whatever it's called.

Thoughts, please?
In the meantime I'm going to read the manual and see if I can make sense of it.
edit: the manual does not provide a diagnostic/pinpoint process for this symptom, and after staring at the diagram for a little while, I am not sure why or how it could have this problem without having another problem too.

[gadget73]

I know there was something about the park cam on these breaking. I believe thats the plastic doo-dad within the gearbox that actually pushes on the switch on the side of the motor to make it park and whatever else it does. I don't precisely remember what the symptoms of that breaking though, but it was either stopping at the A pillar, or failure to reverse the motor to pull the blades down below the hood. Maybe pop the motor apart that doesn't work at all and see if that makes sense. I believe you could buy just that piece once upon a time so that tells me it shouldn't be a huge issue to swap.

[kishy]

The switch is operated by guides or channels that are molded onto the plastic gear of the wiper motor. At a glance, the channels didn't seem to be broken, but I will look much closer.

I went to the junkyard to return my dead wiper motor today, but before I did, I gutted it of the plastic gear in case that is the problem. In doing so, I discovered why the motor was seized. The metal shaft which is manufactured into the plastic gear was completely seized in its bore/probably a bushing due to rust. I smacked it with a hammer a handful of times and got it out mostly undestroyed.

I'll stare at it some more tomorrow and see what sense I can make of it.

[kishy]

I compared the gear from the seized 93 LTC motor to the gear in my 94 FCV motor. The channels for manipulating the switch appear the same between them, and appear to be undamaged.

I cracked open one of the switches and studied it a bit. I cleaned everything with electrical contact cleaner and a wire brush. I bent the circular contact disc thing to make tighter contact. Reassembled and tested, found it still pauses at the pillar.

[sly]

Yeah... that's a new one on me. Haven't ever heard of that happening.

[gadget73]

I think its the tiny crank looking thing that pokes into the cover that breaks and causes problems. Looks like yours is fine so not it.

https://charm.li/Ford/1994/Crown%20V...al%20Diagrams/

has the diagram, maybe that will yield a clue.
https://charm.li/Ford/1994/Crown%20V...ration%20Test/

some diag stuff that may or may not be of use.