Lost all electrical, then it came back. What's going on here?

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cruiser

cruiser

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Hello all voltage experts! I had an interesting incident in my very stock and original 1974 Duster and am wondering if anyone can explain what happened. My three speed windshield wiper motor had just been rebuilt, and I installed it this weekend. The rebuild job looked fantastic, and all wiring was correct to and from the motor. As soon as I tried to run it, the motor jammed and then seized due to a mechanical fault in the motor transmission. Shortly thereafter, the entire car went dead, so I immediately turned the wiper switch off. About thirty seconds later, all power came back on all by itself. The wiper motor was still inoperative, of course. Can anybody tell me what happened? It was as if a circuit breaker somewhere overheated, then closed itself when it cooled down 30 seconds later. I'm not aware, however, of any circuit breakers in the main electrical feed. There is a device called a "fusible link" in the main feed by the firewall, but I have no idea what it does. So here's the question, Mopar voltage experts: Why did my power fail, then fix itself and come back on? Why did the wiper motor seizing cause this? And by the way, this is the second time this has happened to my car. Ideas?

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It may have a bad connection at the firewall connector and when the extra load of the seized motor cause an amperage draw, the bad connection showed up. It's one thing to inspect. That's where I would start. Besides getting the motor repaired of course. lol
 
Rusty, before I installed the rebuilt motor, I very carefully cleaned and filed the eight female cavities in the connector at the bulkhead disconnect on the engine side. I then hit all eight cavities with electrical contact cleaner spray. So I'm thinking that there was not a lot of electrical resistance there because I cleaned it up really well. Whaddya think?
 
4spdragtop said:
Did u try the motor with linkage unhooked?
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No, I didn't bench check the motor prior to installation as I assumed that it was good having just being rebuilt. I sent the motor back to the guy who confirmed the transmission fault, and he has now corrected it. He bench tested it at his business and is shipping it back to me. He said that I don't really need to bench test it prior to installing it again, and that it should start right up. I'll be sure to post my results when the motor gets back to me in a few days. And yes, the wiper linkages were not hooked up when it failed on me.
 
cruiser said:
Rusty, before I installed the rebuilt motor, I very carefully cleaned and filed the eight female cavities in the connector at the bulkhead disconnect on the engine side. I then hit all eight cavities with electrical contact cleaner spray. So I'm thinking that there was not a lot of electrical resistance there because I cleaned it up really well. Whaddya think?
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Maybe. It's still worth inspecting, since it is easy to do. I would also inspect the connections at the ammeter as well as the welded splice behind the cluster. .......and ALL grounds. Even the battery terminals.
 
RustyRatRod said:
Maybe. It's still worth inspecting, since it is easy to do. I would also inspect the connections at the ammeter as well as the welded splice behind the cluster. .......and ALL grounds. Even the battery terminals.
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Okay, Rusty. I'll do all that. But I'm still puzzled by the "circuit breaker" effect that I experienced. There has to be a CB somewhere in there that cooled down and reset itself. I cannot find one anywhere in the FSM wiring diagrams, just the fusible link which I don't understand either.
 
cruiser said:
Okay, Rusty. I'll do all that. But I'm still puzzled by the "circuit breaker" effect that I experienced. There has to be a CB somewhere in there that cooled down and reset itself. I cannot find one anywhere in the FSM wiring diagrams, just the fusible link which I don't understand either.
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Could be....but I've also seen loos cables and loose grounds do similar. Very similar. I'm not familiar with your year model.......but I don't THINK it has a circuit breaker. It might though.
 
Something got hot quickly, expanded, and broke connection. It re-established connection after it had some time to cool. Along with all the bulkhead connectors, I would make sure that fusible link connection is solid. What you experienced is exactly what happens when the fusible link goes open-circuit, except the fusible link doesn't come back. It's great fun losing it at nearly triple-digit speeds northbound on I-43 at 2:30AM, trust me. You lose everything but your ability to pray.
 
I'm no wiring expert but as I understand it, A fusible link is there to prevent an overload in the circuit. It will "burn up" if an overload or short occurs and would need to be replaced if it does. It is a "one time use" piece if a short occurs.
 
On the 3 speed wipers the switch has a circuit breaker on the side.
Check your linkage as if it is upside down it will function but will bind up and cause issues. Easy to reinstall with the square block that bolts to the motor at the 6 o’clock when it should be at the 12 o’clock.
Don’t quote me on that. It could be the opposite of that. I sometimes forget to take pictures when I take something apart and it take longer than expected and forget how it goes weeks later.
 
The easiest way to diagnose something like this is to start wiggling wires. I have found issues like this numerous times this way from bad bulkhead connectors to MAF sensors and ECM's on computer control cars.
 
Syleng1 said:
On the 3 speed wipers the switch has a circuit breaker on the side.
Check your linkage as if it is upside down it will function but will bind up and cause issues. Easy to reinstall with the square block that bolts to the motor at the 6 o’clock when it should be at the 12 o’clock.
Don’t quote me on that. It could be the opposite of that. I sometimes forget to take pictures when I take something apart and it take longer than expected and forget how it goes weeks later.
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Seriously? Is that what that is? I always wondered what that was.

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That just looks like a ground link. Maybe there is an internal cct breaker inside the wiper motor?
 
Bewy said:
That just looks like a ground link. Maybe there is an internal cct breaker inside the wiper motor?
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Even if there was an internal CB in the wiper motor, how could that kill the entire car's electrical system?
 
kdbunn said:
Seriously? Is that what that is? I always wondered what that was.

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That's a ground link.

Actually, there's a resistor/capacitor assembly according to the folks that rebuild 'em. It's built into the bakelite on earlier switches and piggybacked on later ones ('72-up on A/E). There's considerable extra cost involved in the rebuild if yours is missing or shot for some reason.

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cruiser said:
Even if there was an internal CB in the wiper motor, how could that kill the entire car's electrical system?
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Easily. If the firewall main connection, amp meter bolts, bad positive or neg. cable or fusible link is weak, it may not handle the high current load of a jammed wiper at say, 25 amp. The breaker trips at 30, resets as it cools, and then the wiper is off so the amp draw goes back to much lower.

Take a Packard 56 male connector and make sure the two main dash side connectors have tension. The heavy wires for the fusible link and alternator feed. If it slides in and out too easy, that Packard connector has overheated and lost tension. Replace it.

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NoCar340 said:
Something got hot quickly, expanded, and broke connection. It re-established connection after it had some time to cool. Along with all the bulkhead connectors, I would make sure that fusible link connection is solid. What you experienced is exactly what happens when the fusible link goes open-circuit, except the fusible link doesn't come back. It's great fun losing it at nearly triple-digit speeds northbound on I-43 at 2:30AM, trust me. You lose everything but your ability to pray.
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I've had some Strange Stuff happen before too...... maybe I'll elaborate. Some crazy stories! If o wrote a Biography, lefty would list it as Fiction!
 
If it was me, I would make sure to take wiper arms/blades off before turning on motor. Saves scratched paint if orientation is incorrect
 
Have you started the car since this happened? If it is a loose battery terminsl it will often show up when you crank it.
 
Syleng1 said:
On the 3 speed wipers the switch has a circuit breaker on the side.
Check your linkage as if it is upside down it will function but will bind up and cause issues. Easy to reinstall with the square block that bolts to the motor at the 6 o’clock when it should be at the 12 o’clock.
Don’t quote me on that. It could be the opposite of that. I sometimes forget to take pictures when I take something apart and it take longer than expected and forget how it goes weeks later.
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So does the 2 speed! This is why I use the +12v from the motor to the choke feed in my 69. I do not mind loosing the wipers until I can unhook the choke if there is an issue!

Why the OP lost all power is another issue, but likely relates to a breaker type trip!
 
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