3-speed wiper motor cycles once and stops?

Posted By: sixpackbird

3-speed wiper motor cycles once and stops? - 01/21/14 07:56 PM

I have a 1971 Cuda with rallye dash and a 3-speed wiper motor, when the switch is turned on the motor cycles once and then stops, it does not park, stops at the lower end of the wipe cycle. Has anyone experienced this issue?
Thanks

Posted By: Stanton

Re: 3-speed wiper motor cycles once and stops? - 01/21/14 09:02 PM

So what do you do when it does that? Does it do it on all three speeds?

Posted By: sixpackbird

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 04:11 AM

When the wipers stop moving I turn the switch off, it appears to do this at all speeds, but I need to confirm this, so far I am turning on to the low speed and this happens.

Posted By: Stanton

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 04:36 AM

The speed of the motor is determined by resistors in the switch. A dry windshield will increase the load and couple that with the reduction of power and maybe even a low battery and voila, you have wipers that stop where they shouldn't.

1) try the switch in all speeds
2) disconnect the linkage and see if its still a problem

Oh, here's something to check ... when the wipers stop, is the motor still turning? If so, the big gear in the transmission has stripped teeth.

Posted By: ns1aar

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 06:43 AM

If you turn the switch off does it park? If not how do you get it to return? Did this happen after a motor replacement?

Posted By: 383man

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 10:39 AM

Quote:

The speed of the motor is determined by resistors in the switch. A dry windshield will increase the load and couple that with the reduction of power and maybe even a low battery and voila, you have wipers that stop where they shouldn't.

1) try the switch in all speeds
2) disconnect the linkage and see if its still a problem

Oh, here's something to check ... when the wipers stop, is the motor still turning? If so, the big gear in the transmission has stripped teeth.

I may be wrong but from what I remember none of the Mopars in the muscle cars years used a switch with resistance in it other then for intermittant wipers. I believe the 2 speed wiper used a resister mounted on the wiper motor for low speed and the 3 speed wiper motors used shunt windings to change the wiper speeds. But to me if yours stops at any place on the windshield it sounds like a motor problem or bad motor ground. If it stops at all different places it does not sound like a park circuit problem which a park circuit could be the switch or motor but that would usually stop in the same place at the bottom of the windshield. Ron

Posted By: Stanton

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 04:49 PM

Hmmm, you may be right about the switch and shunt windings. There are 4 wires going to the motor so you're probably right. I have a switch out in the shop and I'll look at it later (I'm sure it has resistors on it though).

Posted By: sixpackbird

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 07:57 PM

Thanks for all the input.
The car has been at the body shop for a while, nothing was changed in the IP or the motor. I will be at the shop tomorrow night at will check what happens with all speeds and check the ground to the motor and the switch. When I turn the switch off, the motor does not park, the wipers stay where they stopped at the lower spot on the windshield.

Posted By: Stanton

Re: 3-speed wiper motor cycles once and stops? - 01/22/14 10:10 PM

If the wipers stop with the switch turned on that would be one issue. If they don't park when the switch is turned off that is a different issue.

A proper ground (that brass ground strap) is very important. The motor does funky stuff without it. I spent HOURS chasing problems all because one of the wires is a "ground" and I figured "a ground is a ground". Not so, one is isolated from the other. You need a good ground to the casting for things to work properly.

Posted By: Stanton

Re: 3-speed wiper motor cycles once and stops? - 01/23/14 01:52 AM

Well I checked my switch and there is only one resistor on it and I think its the "low" speed. If I figure it right, the resistor would go to the lower speed windings of the motor for "low". In the second position it would bypass the resistor and go direct to the low speed windings. In the third position it would go to the high speed windings.

Posted By: cuda-sweden

Re: 3-speed wiper motor cycles once and stops? - 01/23/14 07:16 PM

theres a test procedure in the fsm for the motor,if you dont have an fsm i think ive heard passonperformance has the procedure on her website.also make sure your instrument panel switch pod has all 4 screws to mount it installed,one is a ground.

Posted By: 383man

Re: 3-speed wiper motor cycles once and stops? - 01/25/14 08:02 AM

Quote:

Well I checked my switch and there is only one resistor on it and I think its the "low" speed. If I figure it right, the resistor would go to the lower speed windings of the motor for "low". In the second position it would bypass the resistor and go direct to the low speed windings. In the third position it would go to the high speed windings.

You are right as I stand corrected. I looked in my older manuals and the 3 speed wiper system does use a series and shunt winding to control speed but there is one or two resisters in the switch to control how much current goes thru the shunt winding and the motor only has 2 brushes. The more current into the shunt winding the slower the speed and the more current that goes to the series winding the faster the speed. So when a resister is put in series with the shunt winding it lets less current go thru the shunt and more thru the series winding to give a faster speed.
On the 2 speed motor it has a resister on the motor housing and it has 1 ground and 2 speed brushes. It changes brushes from high to low and has the resister in the low speed brush circuit as a current limiting resister. Ron

Posted By: OLD318

Re: 3-speed wiper motor cycles once and stops? - 01/26/14 12:29 AM

FWIW... I don't want to start a holy war here
and yes you can call me ignorant...

I'm just stating my opinion based on years of dorking with
these things..

If nobody else agrees that's cool....

But I think the 3 speed wiper motors on these cars suck....period.
Even brand new/rebuilt working perfectly, brand new switch blah blah
blah, they are lame by today's standards...

I understand this is all due to the design of that time period which is voltage through the switch...

I've never dealt with a 2 speed so I can't comment on those.

I've dealt with A-body B-body and C-body 3 speed motors,
and none of them are anything to write home about..
They are barely adequate AFAIC...

The park mechanism is easily broken.

It doesn't matter if you have an alternator upgrade or
any other electrical upgrades (MAD electrical upgrades etc.)
There is nothing that I've seen or heard about that improves the wiper motor performance to match today's cars..

Again, this is by design (all the voltage through the switch with resistors in the switch etc...)

True, they work...but I'd take the wiper system of my 2000 Buick century or my 2003 F-150 in a heartbeat if there was a retrofit kit
available...

anyway...just my 2cents...