[unruhjonny]

I just refreshed my memory on the precise application of the "1970" wiper switch.

I did this because I thought I had a spare switch that a member here was looking for (it turns out my spares are NOT what he wants).

Over simplified:
1970-1972 = black switch with "WASH" in white print
1973+ = chrome push button with black in background to make the word "PUSH" appear in chrome

I am seeing in my "go-to" MPC (1975 model year) that there are different numbers for:
1) 70-72 with recessed wipers; 1994089
2) 70-72 w/o recessed wipers; 1994090
3) 73 EXC A/C; 1974-ALL; 1994193
4) 73 WITH A/C; 1994145
5) 1975 with recessed wipers; 1994179
6) 1975 w/o recessed wipers; 1994178

I had mistakenly thought that there was one switch that covered all...

I would assume that over time the 70-72 part was replaced with a suitable later part - and that much quicker than this, there was a consolidation of the 73-75 parts.

I have attached images of NOS 1994090, and NOS 1994089;
It looks like the difference between the two is that the lower left connector on the 089 (recessed wiper) is a ground(?) which has an added piece which allows it to ground out in another spot?

Can anyone help to understand the part number differences, and which ones interchange?

EDIT:
The spare I have in hand here is a '178 - this has that same ground(?) as the '089 - except the '089 is for cars WITH recessed wipers, while the '178 is for cars w/o recessed wipers.
THe last three digits of the part number are stamped on the back of the large mounting tab on the top of the switch.
Super confused.

[unruhjonny]

Incase no one replied because I was (as one of my brothers might say) too "wordy";

Differences in appearance aside (when speaking about the pre-delay wiper switches), can anyone help to understand:

1) Functional differences between part number?

2) Which parts interchange?

[unruhjonny]

well, I hope that at some point someone is able to speak up on this matter.

[Ramairnacho]

I bought a whole dash assembly, light switch, wiper switch, guages, and extra bezel. I didnt know there where different switches. Are they interchangeable? If I remember this is nonresessed switch because I actually wanted an extra wiper unit complete.

[unruhjonny]

Originally Posted by Ramairnacho

… I didnt know there where different switches. Are they interchangeable? …

This is PRECISELY what I am trying to understand.

Because I hope to be helpful;
I am unaware of wiring being different, rather the recessed motor and setup doffer from non-recessed;
And right now it looks like the switch is supposed to match the other parts.
The last three digits of the switches full part number are on the back of the switch.

[mlewisariz]

I have 5 switches, all from FB. 3 are 1970, 1 1971, and 1 1975. All have the bridge to ground as the089 shown. I would think that all 2nd gens would be considered to have recessed wipers as they park under hood. Could the 69 be called a 70 in parts books because of the late rollout of the 70? Could the bridge have been added for the "park" function for recessing the wipers? If so, the 090 style may not work.

[Held for Ransom]

My assembly manuals list both 1973 and '74 as the same numbers
1994143 Recessed
1994145 Non-recessed

Picture differences between the 1974 (1994143) and '75 (1994179) Recessed units. Standoff is removed in '75 and a little wider plate (knobs are in two different positions to show width add-on).

[unruhjonny]

Originally Posted by mlewisariz

... I would think that all 2nd gens would be considered to have recessed wipers as they park under hood. …

You are mistaken.

The Esprit and Trans Am came standard with recessed wipers;
The base and Formula did not.

Only cars with standard or optional recessed wipers had them in the park position below the hood line.

[Held for Ransom]

Your biggest problem is you have the PN's reversed.
The 1994145 non-recessed back looks like the 1994090.
The 1994143 recessed back looks like the 1994089.
So, I would say the only difference is the WASH vs. PUSH button.

[unruhjonny]

if by “your biggest problem” you were meaning the item #3 & #4, that was verbatum from my MPC;
I was wondering how in the world the presence or absence of air conditioning would affect the swith.

[Held for Ransom]

No, I guess I'm messed up. Ramairnacho called his unit non-recessed, but it's a recessed unit and I assumed you had the PN's reversed.

Here is a picture of the unit installed in wiring for visual.