Jumping a wiper switch to park blades?

[John Mc]

OK, here’s a weird one. I need a new intermittent wiper switch for my ‘77 Town Coupe. In order to prove my switch was the issue, I jumped the switch by using the continuity pins noted in the shop manual. Worked perfectly, but until I get a switch, I’d like to park the wipers, basically reverse the motor. I’ve tried to retract the blades by following the continuity schedule listed under “park”, but nothing. Can anyone, especially Dan, tell me how I can reverse the wiper motor? I’m no electrical engineer. Please see below, thanks in advance.

[Dan Szwarc]

Post the full picture of the bottom pic and I’ll figure it out.

[John Mc]

Thanks Dan, here you go:

[Dan Szwarc]

Let me see what I can figure out tonight. I'll try to post something by 9:30PM EST.

[Dan Szwarc]

The park/parking/run switch inside the motor only matters if you are trying to debug a switch, etc. Forget that. You want them in Depressed Park.

Do this:

Remove the three terminal connector at the wiper motor.

Verify which terminals on the motor connect to the wire colors.

Jumper +12V to the Yellow-Red terminal and ground to the dark Blue-Orange terminal.

Current path for parking the wipers.

The motor will run backwards and then park. Quickly Remove any wire when they are parked.

The parking action is mechanical aspect of reverse motor operation. The wiper mechanism is designed to pull the wipers down when run in reverse. This is called Depressed Park. It was patented by Ford in 1970.

Normally, the wiper only runs forward, which allows the wipers to move up and down, but it’s actually tracing a circle/oval internally. It just looks like back and forth.

When run backwards, angles of mounting pivots allow the wipers to go lower because of a tricky aspect of torque.

[John Mc]

Dan, that is awesome, thanks for your time. I’ll post my results.

[John Mc]

Perfection! I really appreciate it.

[frasern]

Sometimes, I forget just how much junk I have around here. Note, this is for '79.

I had one of those switches, but sold it last summer. Big car only, It has 9 round terminals, not used after '79. Truck switches were 7, with flat terminals (non depressed) and were used until '91, but are not compatible. They look the same, unless you look at the pins.

[John Mc]

Great information, I have them saved. Thank you.

[Dan Szwarc]

Any luck locating the intermittent switch?

[John Mc]

Any luck locating the intermittent switch?

Not yet………unless I want to spend $250-$300!

[Dan Szwarc]

This wiper stuff is interesting to me because my 70 Mercury has standard 2-speed switch, and my parts car came with vacuum controlled intermittent wipers. The switches are available for both, but I have no idea if the vacuum delay will work and it requires a custom harnesses. I enjoy analyzing schematics and understanding their operation even though my Merc doesn't have depressed park.

Keep us posted! This is fun.

[frasern]

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.

Maybe 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.

[Lee]

Fraser, did you ever see the movie "Flash of Genius"? Greg Kinnear plays a guy who invented an electronic system for intermittent wipers, that Ford supposedly stole from him. Anyway, in the movie, it is implied that he invented the entire concept of interval wipers. Which wasn't true of course, since Ford had used the vacuum system years before. Anyway, that fact would have spoiled an otherwise enjoyable movie. There is a very nice Mark III in it.

[frasern]

I can't imagine Ford ever doing such a thing! preposterous!
Never heard of that movie before, something to keep an eye out for.