I want to still use my good 6volt wiper motor assembly in my 1955 panel truck and have converted to a 12volt system. I installed the correct ceramic type voltage reducer in between the ignition switch ACC pole and the wiper switch. So far the motor isn't moving and voltage reducer is getting very hot if battery is hooked up. Does anyone have any advice? Thanks

 

Sounds like you may have it hooked up bass akwards.

 

Do you have 12Volts neg ground or pos ground? Is 6VDC wired correctly? Does the meter say 6 VDC at the wiper switch?Do you still have your old 6 volt battery? Hook old battery to the wiper switch to see if the wiper motor is at fault internally. Have a great day, chuck

 

You know, my truck is set up like that too, although I didn't do it...I bought it that way. All I know is everything works, so something must be backwards with your set-up. I HATE electrical problems!!!!

 

I have a stock 6v electric setup and tried to run it on 12v off the truck. It worked OK on 6v, but got extremely hot and barely worked on 12, burned up a big rheostat.

 

In order to determine the size of the reducer needed you need to know how much current (amps) that your wiper motor draws (under load with wipers against windshield is best) when 6 volts is applied, you can measure this with an ampmeter. To do this you need to apply ohm's law wherein R=ohms, E=voltage and I=amps. Ohm's law is E=IxR, R=E/I or I=E/R. Say you measure 12 amps at 6 volts. Ohms of the reducer in this case would need to be 6 volts devided by 12 amps (6/12) which would result in .5 ohms.
A way for you to check your present system would be with a voltmeter. Turn on your wipers and measure the voltage at the supply wire to the wiper motor to ground, it should be 6 volts, I suspect you will find a lower reading. You can also read the voltage across the reducer and it should also be 6 volts, is suspect it is higher. If it is higher across the reducer you need to use one with less reisitance.
Power (watts) = I x R so in your case the resistance is to high causing the reducer to use more power than the motor which will cause the reducer to get hotter than it should and the motor will either run slow or not at all. -- Chuck

 

Thanks for advice, I took reducer out and decided to run the 6volt wiper assembly under 12 volt for now. It works fine but very fast. I figure it will be seldom that I need to run the wipers because it never rains in Southern Calif. anymore. I think Chuck is exactly right, the resistance of that reducer was too much. I may find something later that is more compatible.

 

I would not recommend running the 6v wiper motor continuously on 12 v. It will have a very short life. I suggest that you procure a proper load carrying dropping resister. Below is a response I made on a related question on the Forum back in April.


"I ran the 1952 6 V electric wiper setup in Willard on 12 v for years ( and I am going back to that setup) with a large dropping resister specifically for the wiper motor . It is a large wound ceramic style power resister that is adjustable. It is an Ohmite #0956A 1 ohm 100 watt resister. ALBUQ is correct, it provides auxilliary heat! The resister has a slide contact to allow adjustment. I have it adjusted for about .75 ohm which gives me about 7 V at the wiper terminals with the wiper operating. Don't ask me where I got it. I bought it just about 30 years ago! You would have to find a place selling large power resisters (not Radio Shack). The resister is about 6 inches long and 7/8" in diameter. It is a hollow tube style.
I am going back to it after trying to quiet down a setup that I fabbed using a 12v VW setup. The dash in Willard functioned as a drum amplifying the sound of the wiper motor after many sound isolation attempted fixes. I needed the compact size of the 6 V setup with my behind the dash Heat/ AC unit with ducts."


Back in April 2007 I just did a google search. Believe it or not the one that I have was on Ebay #7588203651. It worked 30 years ago and it works now!

Back in April john061543 bought that one following my posting the ohmite #. It may take some looking but you should be able to find one. Try google.