66 barracuda variable speed wiper question

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Syleng1

Syleng1

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Hello Everyone,

I asked this question a while back but the thread was lost. I have a 66 Barracuda with wipers that pop the circuit breaker after about 3 revolutions. I since got a copy of the service manual and the electrical schematics. Now when the circuit breaker pops it turns on the reverse lights. This is totally odd. I followed the schematic and other than both getting a B+ signal from the aux terminal on the key... they are separate after they split.

I plan on removing the switch and disconnecting the it hoping to find a contact out of wack inside the switch, with out cutting the harness I cannot see how many amps the wiper motor pulls even though I have the FSM for diagnostics, I believe it is a bear to remove the motor. So I am hoping to avoid that.

Anyone else had this happen? It happens on the variable speed setting or the single speed setting. I can easily check the grounds and the reverse pull back feature of the motor inside the car... I just have not yet. A new switch is over $150.00 new on Ebay.

Thank you in advance.
Joe
 
Silly question, did you lube the wiper pivots and replace the seals?
 
There are a few things that result in high motor current. Amx364 has suggested the first, something that is locking the motor. The other is an internal winding short in the fields or armature. The third is an open connection on the fields. Without field current a running motor speeds up and draws excessive current. A stopped motor will not start and draws excessive current. Typically the field is two windings, one on each side of the motor, one is connected to full field the other is fed via variable resistor to vary the speed.

To complicate matters the switch arrangement reverses motor direction for park. For this to happen the polarity of the armature needs to be reversed compared to the field.

The factory service manual has information on how to test the variable motor in forward and reverse by hooking up motor connections to a battery in the correct way for forward and reverse. The manual used to be downloadable from mymopar.com. Section 8-80.

It is much work, but it is best to see if the linkages are free first, then test motor, if it works, then it is likely the switch or wiring. Bench testing is best done by removing motor.
 
amx364 said:
Silly question, did you lube the wiper pivots and replace the seals?
Click to expand...

While the windshield and dash were out, I rebuilt the pivots and installed the grease fittings. it all worked fine then. Dash and windshield reinstalled and the wipers were fine. Approx 1,000miles later the wipers started doing this.
Joe
 
Sounds like at the very least the switch may be shorting internally but that motor may be drawing extra amps causing the switch assy to over heat and short. It's not uncommon for the plugs to melt and deform on those switches so be sure to give it a good look over.
 
KitCarlson said:
There are a few things that result in high motor current. Amx364 has suggested the first, something that is locking the motor. The other is an internal winding short in the fields or armature. The third is an open connection on the fields. Without field current a running motor speeds up and draws excessive current. A stopped motor will not start and draws excessive current. Typically the field is two windings, one on each side of the motor, one is connected to full field the other is fed via variable resistor to vary the speed.

To complicate matters the switch arrangement reverses motor direction for park. For this to happen the polarity of the armature needs to be reversed compared to the field.

The factory service manual has information on how to test the variable motor in forward and reverse by hooking up motor connections to a battery in the correct way for forward and reverse. The manual used to be downloadable from mymopar.com. Section 8-80.

It is much work, but it is best to see if the linkages are free first, then test motor, if it works, then it is likely the switch or wiring. Bench testing is best done by removing motor.
Click to expand...

I see that this is the path I must take. I have the Factory Service manual and read the full section on this test. Just getting it out is the tough part... I think.
This weekend I hope to remove it and I want to test the circuit breaker with a amp load tester and see what it pops off at to isolate the switch or the motor. I just cannot figure out for the life of me WHY the reverse lights are coming on when the car is driving in "DRIVE" and the wipers are "on."

The flow of electricity is B+ power to the wiper switch from the aux port on the key switch. Once it goes thru the internal circuit breaker it then stays inside the switch for wiper motor use or goes out of the switch to feed the load side of the reverse slide switch on the shifter. Once the switch is in "REV" it then follows the line out to the rev bulbs. The rev light switch is properly adjusted and working fine. No where do the wipers and the rev line touch except at the switch and even if they did and shorted it MUST go thru the rev switch before it can go out to the rear lights. It is just very bizarre.

I am going to remove the reverse lights from the system and test to see if these still come on or at least what amperage it will pop the circuit breaker. I also need to ohm check the wiring from the wiper switch to the motor. A bad ground (loose ground) would short the motor IF the contacts in the electric motor is drawing too many amps due to worn bushings (excessive load) and touching the case. I did test the linkage from the motor and it moves nice and freely. (is freely even a word?)

OK, just typing to myself. I am all up in my head over this one.
Thanks for the help!
Joe
 
The Violet wire on the wiper switch at the B/U terminal (I think) goes to Backup lights
 
AMX364 - Thank you for your help.
The car is pretty much all 66 and the lighting issue bothers me more than the "no wiper complaint." Removing the center console to get to the rev switch is also a bear for ohm checks. The interior is red and very clean. This makes repairs or even diagnostics even worse because of the grease or dirt that can get on your fingers (even with gloves) and stain the seats or rugs. I get so busy with work that I just want to drive the car sometimes and don't want to waste my little available time working on it. I will rephrase that, I enjoy working on making something better, faster or looking better. I dislike repairing something that takes a lot of time to diagnose and then waiting a few weeks for a part to be available before I can reinstall it to be able to drive it.
 
Here is a quick update:

I ended up finishing up early today and decided to work on the Barracuda since it was 40degrees out and not raining (Heat wave here in CT lately)
I ran thru all the diagnostics in the service manual and the help from people on this board. The reason for the circuit breaker popping off was not from a bad switch or wiper motor. It turns out the spring must be weak in the switch for the electric washer pump so when I was turning on the switch the washer was engaging and the pump I just put in this time last year is junk! It is locked up and seized (only used washer solvent that was not diluted) It must had been the issue for a while now. If the switch can be rebuilt I will have it done next winter but for now I am going to be gentle and actually pull it out as I am turning the wipers on. What a fluke!

Still trying to figure out the reverse lights coming on when the circuit breaker pops open. I am going to wire the reverse circuit directly to a aux circuit breaker rated for 2@ #98lite bulbs. My calculations are a 7amp breaker should be correct. I ran thru the whole reverse light system today and it all tested good.

I will keep this going with updates as long as it is doing anyone good.
Thanks again for the help,
Joe
 
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