Wiper Motor Difficulties

[hog]

This is a diagram I used in my Shell Valley. It works great provides 2 speeds and parks the wipers correctly. You need a double pole double throw switch and a couple of relays available from Jameco Electronics. They also have the sockets for the relays. http://www.jameco.com/
Hog

[Steve R]

Gary,
O.k. It makes sense that the wipers will run in low, high, and will park most of the time under the condition you described. (the hot lead removed from the wiper motor plunger switch)
Under the following conditions you will note it does not work correctly: Turn ign key on, Turn wipers on, Shut ign key off when wipers are in mid stroke. They will stop in an other than parked position. Now move the wiper toggle switch to the park position. Wipers still do not do anything. now turn the ign switch back on. The wipers still will not go to park because they are not being suplied power at the plunger switch due to the wire being off the terminal. Now plug the wire back where it belongs, and the wipers will move to the parked position.
Simple eghhhhh?????
Steve
P.S.
I believe the hot lead to the wiper motor plunger switch is intended to be hot all the time, regardless of ignition switch position. (this is the way I have my car wired) thus my wipers will always park when commanded to do so by the toggle switch whether the ignition switch is on or not. I'm not sure where the practice of wiring both power sources to the ignition switch as suggested by the Finishline print got started, but I believe that is the incorrect way of wiring it.

[G.R.]

DUH---I just went and tried that--did just what you said--plugged the motor lead back on--I had tested it with it off and it parked by it self, never tried it again until now--parked any where in the cycle---hooked the motor lead up parks cycles and parks all the time.

Steve I owe you one I feel like a real dum-dum, so simple now that I understand what is happening. The motor has power off the switch so it will run but not properly, that is why it was suggested to run the 2 hot leads seperatly.

Life is good now fixed my other electrical gremlins today now I can put the dash back in

[Steve R]

Gary,
No problem buddy. When I first started to try and understand how the Lucas wiper sytem works, I asked many people. They could tell me how to get it to sort of work, but I could not find anyone who could explain the whole thing to me, to my satisfaction. So one winter day I sat down with the motor, toggle switch, jumper leads and a meter at my kitchen table. ( I parked my car outside and ran a set of jumper cables from it through the kitchen window for power) I played with it until I had a good idea of how it operated. Then I got a piece of paper and a pencil and used my ohm meter to make a truth table for what the toggle switch does internally. I then devised the schematic to show that info.
I then dissasembled the motor and removed the plunger switch assembly. I made a truth table for that one also. then I devised it's schematic. I then made a mechanical schematic of how the cam on the gear interacts with the plunger switch.
Finally I put it all on the drawings you see here.

I still could not for the life of me undertand why they gounded the normally powered side of the motor's winding when in park. Many months later I happened to be thinking about that question (it was bugging the hell out of me) one day, While working on my friend's Classic Roadster I was messing with the pusher fans. (you know, the ones that came on the real cobras) They were connected electrically to each other but not to the car. I spun one fan with my finger and to my surprise the other one moved! OH, YEAH, the motor I spun acts as a generator when moved by an outside force. the power it made moved the other motor. Still fooling around with them I held one fan blade still while I turned the other one..... It was harder to turn. Hmmmmmm. Then the light bulb in my head went bright! thinking back to the wiper motor, I realized It's a magnetic brake when the windings are grounded by that plunger switch!!!!! They did it that way so the cam does not glide past the plunger.

I spent a lot of time to figure it out. That is why I don't mind sharing the info.
Steve

[Steve R]

Jim,
I tried to answer your question in my first reply. Go back and look at the wire diagrams and explaination I posted. Take the time to really study the path the power takes in each mode. Take 2 advil and Reply in the morning.
Steve

[G.R.]

PNJSNAK---things I learned in this process--

1) you need a Lucas part #35927 wiper switch, it has an internal park control

2) you need to seperate the "hot" leads from the switch and the motor, other wise they have a tendency to not work right---don't have the motor and the switch going to the same fused lead or ganged together.

3) As Wilf and Steve pointed out the wipers will never work right without the Lucas switch

4)You might have the same problem I encountered---the wiper motor "hot" lead is either disconnected or is sharing the same power source as the switch if you have the Lucas switch.

5)Paitence----it helps when you are ready to scream $#!t and start throwing tools

I can disconnect my battery switch, turn it on and the wipers will cycle and park, turn the car power on the wipers do the same. So far my electrical life is good

If you are only running a off-on-on toggle switch your wipers will not work right.----the Lucas wiper switch is the key it controls the park function internally.


Thanks to all for helping me figure this one out and Jim, hope this makes sense

[Michael C Henry]

So what you'er saying is -power to dash switch switched by ignition switch-power for park supplied to wiper motor not switched by ignition switch. That's doable. The result would be if you cut the ignition before wipers park ,they will go ahead and park and you wont have to turn the ignition on again to let the wipers park.
I still do not see the ground switching .Their is no ground shown at the Dash wiper switch.When the dash switch is in a park-off position and the wipers haven't come to the park position .Power supplied that is at the motor park cam operated switch is sent back to the dash switch via the park wire.That is internaly connected to the low speed inside the dash switch when in park -off position. That power is returned to motor via low speed. and is interupted by the wiper motor cam switch when park is reached.

[Steve R]

Micheal,
Scroll up a bit and look at the diagram. Look at "#2 park" on the dash board switch. Follow the wire to the motor plunger switch. The plunger switch is drawn compressed by the cam. It's lower contacts are drawn supplying a path to ground.
Go back to the "2 Park" terminal on the dash board switch. Follow it in the other direction. You will note it leads to the "slow" winding in the wiper motor. Keep following in that direction and it will also lead you to ground........ both sides of that winding are grounded when the wipers are parked.
That is the ground circuit that makes the motor come to a screaching hault. (you can hear it actually "screach" to a hault.) If that winding does not get grounded in that way, the wipers will just come to a stop when they run out of momentum, or even skip over the cam for another cycle.
Steve

[Steve R]

ttt
I don't want this thread to disappear into the sands of time. It has some great info.
Steve