Wiper speed control switch

Here is a idea I had with my yj but never did it. Now, I need to wire the 69 and it gives me a chance to try it.
Simply, wiring my wiper motor using like a headlight dimmer switch of sorts to provide full control of the speed. You would turn the dial up to go faster and down to go slower. This would also let me stop the wipers at the bottom of the windshield.

Just curious if anyone has done this. Any complications(like the motor dieing prematurely due to the draw during the low speeds) and what they used as far as a switch, wiring, etc. Thank you

 

You'd need a pretty high amp capacity rheostat to do that. Remember, the dimmer built into the headlight switch only controls a few lights so the draw is pretty minimal. By contrast a wiper motor draws several amps and at startup can draw quite a bit so a headlight dimmer would not have the capacity. There might be a higher amperage/wattage rating unit out there that would work though.

 

I believe the two-speed wiper motor works by having two field coils. The motor uses a shunt field that is either in or out of the circuit to adjust the speed of the motor. They disconnect the shunt field (opposing field?) to make the motor run faster... no rheostat is used.

Electric motors can be difficult to make run slowly. If you reduce the voltage, they tend to cog and stall. Back when I was a model railroader (when I was a teenager), we used pulse length modulated DC supplies in order to give the realistic slow starts we wanted. The easiest control is an SCR that you turn on and off repeatedly with a timer. The knob then controls the timer interval. Your variable speed electric drill likely works this way.

I suspect the rheostat scheme would not give you the performance that you want.

 

pretty simple switch to begin with on the stock setup, just power out on 3 wires and all the switch does is transfer the power to the correct wire. power to low speed, power to high speed (its a two speed motor) then believe it or not power to the third wire to park the wipers. they use to make a intermediate add on for vehicles that didnt come with intermediate wipers

 

That is where i see this being a issue. During days where I get like a mist off of cars in front of me I would have the wipers moving very slowly causing that motor and switch to heat up. Think that's why they have a timer on modern wipers. I am willing to swap out the motor with something larger to make this work. It is on my list of things to simply replace anyway. The idea of the wipers at the bottom of the windshield with the motor off is the goal.

 

If I'm remembering correctly, they used to sell kits to make wipers intermittent before the feature became standard on all cars. Perhaps there may still be some of the kits available in the aftermarket.

 

The new replacement motors are like 12 bucks each, and they have an auto shutoff, i.e. if you turn them off they will complete their stroke and stop wherever you bolted the wiper to stop.

You have to change your old short shaft with their new long shaft, but thats it.

Pretty simple.

Dont get too complicated, I am an engineer, and I could give you hundreds of ways to do this, just replace the motor with the auto shutoff. You can buy them from Walcks or KaiserWillys, but Walcks will be a better deal!

Kurtis

 

They all work better than my original 1960's, and my old ones do function, but not as well. The key is saving your old shafts as you need to use your original short shafts. Dont diss new parts, I would much rather have my 12V wipers than what was original, i.e. the vacuum setup! Original is good, but sometimes safety is more important!

 

Oh yes, I used the original Vacuum ones, the first "used" 12V ones, and my new ones. The new ones are far superior to either of the previous ones!

Why? What is your point? That the Vacuum ones are better?

Other than them wiping "faster", you have the same problem at lower RPM, they wipe slower, the 12V are consistant. So I dont quite understand your comment. And as a safety feature, YES, I do belive that the 12V wipers are better! Otherwise, if you are talking install, then maybe you have done them incorrectly.

 

Well said. The new motors I have work just fine, the old motors, that stutter are on my shelf if I ever need them. The new motors have been exposed to many a rain fall.

Just FYI to any other newcomers to wiper motors, the new ones have some flanges that dont match up exactly to the old ones. I used my old gaskets along with the new ones, it prevents any water penetration. If you just swap out your old cam/shafts from you old 12V wipers, you will have a gap, letting water into your "new" wiper motor. If you dont have an old gasket to use, you can always run a bead.

 

My point exactly! :dead horse: