[27Tall T]

I have 2 universal wiper motors that I have wired together They are wired as follows:

The negative terminal (-) goes to ground.

The positive terminal (+) goes to a fused power source.

The switched terminal (S) goes to one side of a toggle switch and to ground from the other terminal on the toggle switch.

This is not a "Mighty Wiper" brand as their wiring is not as above.
My problem is that when I start the wipers they work and if after a few seconds I shut them down they will shut down. However, if I leave them on for more than say, 20 seconds, and then shut them down, they won't. They keep on running. Sometimes (rarely) they will shut down, but more often than not they won't. I've been told that a diode is needed as there may be some feed back. There are no relays in the system and I don't want to rewire the whole system so that each wiper has it's own source. Each wiper comes from a common feed and each wiper comes from a common ground. Question.....what type and size of diode do I need and where does it go?

[ogre]

is this a new install or an old install?

your running 2 motors with one switch, i assume that the switch grounds the motor and when you switch it off the internal park switch grounds it until the motor parks. if the motors are getting out of sync after running for a minute or 2, when you turn the switch off, each motor is grounding the other motor thru the park switch.

what i mean by getting out of sync is one motor is running a little slower than the other one. they both start out going left, right, left; but after while you might see them going opposite of each other or slightly out of whack with each other.

try running each motor separately to see if both motors park right after 2 minutes. if they both work fine then either use: a DPST (double pole, single throw) switch to separate the grounds. or if the switch matches your other interior switches, use 2 relays to disconnect the grounds.

a 1N4001/L diode would work if you had feedback thru a relay. a relay take a small load to energize. a 1N4001/L diode will not take a lot of power, such as a motor load. you could buy a big diode but it would be cheaper to try either suggestion above.

either way write back if this works...

[27Tall T]

No this is a new installation. I thank you for the info. Being so close to Christmas I probably won't be able to do what you suggest until after the holidays. I know what you mean by being out of sync., but I'm wondering if there is any way to run them into a common sync? Reason for asking is that these are mounted on a '32 Tudor and the windshield is not that big, so there might be an overlap of the blades which could cause a problem.

[ogre]

i drive my truck everywhere in all weather (no salt), i use rain-ex and have never turned my wipers on. i have the arms and blades mounted in case i run up on a truck spitting mud, but have never used them. we ran all day in the rain from indy to muskegon on the HRPT. never turned them on.

[27Tall T]

I believe in Rain-X too! It's wonderful stuff and I would probably run without the wipers in place, but the challenge is to see this thing through. Had some time today and disconnected one wiper. Works and parks! Did the same for the other one. Works and parks! Ran them both together and saw that they were definately out of phase, but they did stop when shut off. BUT, one parked and the other didn't. Now if I used a diode, where would I place it and would this cause both wipers to park? Really appreciate the feedback.

[ogre]

you're still better off with a DPST switch, but if you insist on using the diodes...
the 1N400x diode is only rated for 1 amp, you will need to do a little research on diodes to figure out which one to use with a motor.

this is a radio shack 3 amp diode for $1.79

[Joe G]

Originally Posted by 27Tall T

....Now if I used a diode, where would I place it and would this cause both wipers to park? Really appreciate the feedback.

You would need to use two diodes, one on each of the 'S' wires. Like this:



However, I agree with Ogre that it would be better to use a DPST switch.



The choice is yours.

Hope this helps....

[27Tall T]

I can't thank you guys enough. The switch that I'm using is a universal SPST lighted one thats fits into a rectangular hole. Now the search is for a DPST that will fit into this hole (may have to widen the hole somewhat, which is okay).

[OLNOLAN]

Hey Tall T, If you can't find a suitable switch, you can use a relay in place of the DPST switch. You'll need an automotive 12vdc DPST relay or two SPST. Heres a DPDT from Radio Shack that would work, 10 bucks;
http://www.radioshack.com/product/in...rodsPerPage=60

Food for thought. Nolan

[ogre]

yes, like joe says

nice pics joe

[jimmothershead]

Hate to pop your bubble but the arms will never syncronize in motion with 2 wiper motors.

What car are you working on ?

Check the load capacity of the switch always. One will work. Don't need double pole. Are they 2 speed ? A dedicated ground is required.

[27Tall T]

Originally Posted by jimmothershead

Hate to pop your bubble but the arms will never syncronize in motion with 2 wiper motors.

What car are you working on ?

Check the load capacity of the switch always. One will work. Don't need double pole. Are they 2 speed ? A dedicated ground is required.

I'm working on a '32 Ford Tudor and yes I realize that the arms will never synchronize. The switch(SPST) that I'm using is rated for 15 Amps. They're single speed and they both share the same ground. My only concern is to get the wipers moving so that I can safety the car to the satisfaction of the inspector. After that Rain-x will be my wiper mode.

[jimmothershead]

27........Done a many '32 stock & street rods. Yes, you do have the bulkhead opening on the right side...for export right hand steering.
Why does inspector require dual wipers if it did not come with dual wipers ? Titled as a '32 ? What State ?

[27Tall T]

I'm in British Columbia and because it has been modified (read street rod) it's now subject to new rules and regulations.