Jumping a wiper switch to park blades?

[Dan Szwarc]

Interesting, I have never heard of a vacuum controlled system, my '71 LTD, I am sure, had the same system as Johns car.
I put the control from an '89 truck in my '67 and it was the simplest upgrade imaginable, I had to cut about 1/2 inch off the shaft, for the knob to sit right, but plug and play otherwise. The control has two pigtails, one for the switch and one plugs into the similar end where the old switch was. I have one of those here I can photograph, if you want.
Johns car is similar, if you look at the wiring, you will see the box is plugged into another plug, which could accept a regular switch.DSCF9360.JPGMaybe this will better explain, it is from an 80s truck, but if your '70 Merc. has that plug (cut end) and a rotary switch, the intermittent switch and box will just swap in without any other mods.

Lookie what I found in my attic.

This was pulled from a 79 Collectors Series Continental. It matches the pinout of my 70 Merc harness and likely my switch.

I have to admit that the vacuum unit is actually really cool, too, but I doubt it still works. I'll post pics of the controller when I locate it.

[frasern]

I'm pretty sure that's the switch John needs, with the round pins, depressed park, It is what was in my '79 Mark, which I sold last summer. The one I posted is for non depressed park.
The switch end has lugs to prevent a non intermittent switch from fitting.

[John Mc]

Interesting, I have never heard of a vacuum controlled system, my '71 LTD, I am sure, had the same system as Johns car.
I put the control from an '89 truck in my '67 and it was the simplest upgrade imaginable, I had to cut about 1/2 inch off the shaft, for the knob to sit right, but plug and play otherwise. The control has two pigtails, one for the switch and one plugs into the similar end where the old switch was. I have one of those here I can photograph, if you want.
Johns car is similar, if you look at the wiring, you will see the box is plugged into another plug, which could accept a regular switch.DSCF9360.JPGMaybe this will better explain, it is from an 80s truck, but if your '70 Merc. has that plug (cut end) and a rotary switch, the intermittent switch and box will just swap in without any other mods.

Lookie what I found in my attic.
IMG_4462.jpg
IMG_4463.jpg
IMG_4461.jpg
This was pulled from a 79 Collectors Series Continental. It matches the pinout of my 70 Merc harness and likely my switch.

I have to admit that the vacuum unit is actually really cool, too, but I doubt it still works. I'll post pics of the controller when I locate it.

Dan, here is the switch with the proper 10 pins.

[Dan Szwarc]

I'm pretty sure that's the switch John needs, with the round pins, depressed park, It is what was in my '79 Mark, which I sold last summer. The one I posted is for non depressed park.
The switch end has lugs to prevent a non intermittent switch from fitting.

John needs the switch; not the intermittent module.

I looked for a switch in my attic and I’m surprised I have this and not the switch. I’ll check again when I can as I have also found many other modules.

John, did you try opening the switch and cleaning it out? You might be able to restore functionality.

[Dan Szwarc]

The switch is base PN 17A553.

For 1973 to 1979, part number is D8LY-17A553-B or Motorcraft SW-1479
Same for Continentals and Marks.

The A version is without Intermittent.

There's five out there via RearCounter.Com

[TonyC]

Dittos on the repair-first route; if the plastic harness or any wire to it doesn't show signs of melting, it should still be repairable.

---Tony