Ignition Switch Connector Fail

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Duster7286

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Took the Dart out for a spin today after setting timing, all going well, turn the corner and car shuts off, lost all power. Pull over, reached under dash jostled the ignition switch connector and I was back in business, got home and took a closer look, the large red wire of the ignition switch connector was loose and not seated in the connector properly, connector was burning hot. What is the best way to fix this? Replace switch- connector? Or simply place new terminals on each end of red and reconnect? Thanks!!

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What is the best way to fix this? Replace switch- connector? Or simply place new terminals on each end of red and reconnect? Thanks!!

If you can get the proper connectors and the proper crimp tool that is the route I would go. I would try to find a replacement for the plastic connector part that melted look at rock auto they have some connector parts these days. There are pin removal tools, check ebay and Grainger / McMaster Carr.

also a parts car wiring harness would have the plastic and pins, you could solder the wires directly to the pins then replace the plastic part, just be sure that the soldering does not create a pin too large to fit into the plastic.

For the sort term you could mate the two connectors external of the plastic and tape well.

I would look for a reason the connector got that hot, it may have been simply a bad connection or the pins did not seat correctly in the plastic and each other, but better safe than sorry.
 
I would give your wiring a good check. Could be a fire hazard there. I believe that red wire goes to a factory splice under the dash and connects to 4 or 5 wires. Splice may be wrapped in a cloth tape. I would dig further, but we all know what happens.....
 
Every single one of us should have a fire extinguisher in the car. Period. That said...

Reconnect that and see how hot it gets with the car running. Excessive heat means a high current flow through that circuit. The two should fit together snugly. See how tight the individual wire is in the female end it goes to.
 
Every single one of us should have a fire extinguisher in the car. Period. That said... .
Saved my *** for sure with a engine fire. A 2lb just did it I carry a 10 now. That plastic housing is now toast since it got melted internally a new terminal will never lock in. I would change it and the pin. Then look for the cause. It can be just that connection better to be safe though and look at everything in that circuit. I know it sucks.
 
That is arcing / over heating and that means you have too much draw on the system. Somewhere you have an item or a short drawing more amperage than the wire can handle. Electric fans should be wired thru a relay or stereo amps thru a relay. If you are bone stock and don’t have any of that verify your wiring. And I totally agreed with a fire extinguisher in the car. Even one under hood and trunk.
We all dislike our babies going up in smoke but waiting for the local fire department to show up can sometimes take a awhile. You are very lucky my friend. Keep us posted.
Joe
 
That red wire feeds every circuit except those hot at all times, i.e. headlights, brake lights, cig lighter, dome lamp. It a somewhat common point of failure too. The next weakest link in the path is the switch itself, mounted up in the column, the fusible link, or wiring. Where we would rather have a failure occur is evident. And like the madelectrical bulkhead connector bypass, we can over fix which moves the point of failure.
We can't be absolutely sure this is the slow, heat and reheat over time to eventual failure, or a sudden failure caused by a short circuit elsewhere. We don't know what aftermarket electrical loads you may have added. the OEM loads can be enough to cause this failure. Largest OEM loads are wipers and blower motor. Add all the park lamps, etc,,, it adds up.
For the 73 Valiant daily driver we had for many years... All OEM with a/c, same harness connector failure, it started busting the replacement wiper linkage bushings every 16 months or so. Binding wiper pivots was the route cause and I suspect that contributed to the electrical overload.
That same car also melted down another white harness connector at back of right valve cover ( engine harness connector ). I don't recall the time frame between these failures. I have no clue how one failing connector might have contributed to the other. If you find a fault there, that connector can be completely deleted with butt connectors. It was only added for ease of assembly.
In the end we are working with very old electrical components that were minimally adequate when new. We're lucky they fail how and where they do, whether we believe "by design" or not.
 
Thanks everyone for your help, guess I have some digging to do! *and a fire extinguisher to buy* Time to do the alternator bypass too..
The only aftermarket item is a stereo previous owner installed. He had spade connectors slid on the fuse clips to power it..while looking at the ignition switch wiring they came off so I am gonna leave it disconnected till it can be done better.
I pushed the pin into female side and is tight however the pin does not hold at all in the burnt connector obviously. If all the wiring checks out good should I just replace the entire ignition switch or seperate the thick red wire to a seperate connector--I noticed that on the replacement switches (standard brand) has the thick red and black wires seperate from the white connector.
 
Hint on fire ext. Get a co2 or argon. The powder is severely corrosive and it is a super PIA to clean up. Hopefully you will never need it.
 
What is the best way to fix this? Replace switch- connector? Or simply place new terminals on each end of red and reconnect? Thanks!!
IF the metal terminals will be retained the connector, you can continue to use it - at least for now.
If the terminals are not retained, when the connector halves are pushed together the terminal will back out. Result will be a poor connection.

I'd remove the terminals that show heat damage and check each for corrosion, and condition of the crimp and wire strands. Then decide if they should be replaced.

Yes. Look for a new or good connector, even if you don't need it right now.

Next. As Redfish was pointing out, find the reason it overheated.
1. Poor connections - either at the connector or downstream.
2. Excess power draw down stream.

This is a situation where measuring for voltage drop should reveal high resistance in a circuit.
Remember, for voltage drops to occur, there must be current flowing through the circuit.
If you do some of this testing with the engine off (key on), observe the ammeter for each test. If there appears to be high flow for a device, then the cause is more likely the device or a short.
 
Electrical FIRE
First thing to do: Kill the Power feeding it!

1 Shut off ignition.
2 Then if neccessary open the hood and remove the battery connections. Ground first.
Careful in opening the hood. If you open it like normal you will be standing right in the supply of fresh oxygen for an underhood fire if there is one.
 
Battery quick disconnects can be cheesy but this is why I run them. Almost lost my car to an underdash short when I let my ex-girlfriend drive it.

Fire extinguisher and fuses and RELAYS RELAYS RELAYS
 
Battery quick disconnects can be cheesy but this is why I run them. Almost lost my car to an underdash short when I let my ex-girlfriend drive it.

Fire extinguisher and fuses and RELAYS RELAYS RELAYS
There are battery disconnects that use a battery terminal end so if you have a genuine battery terminal you don’t have to cut your good cables to use. Also they make for good theft prevention. More great points !
 
Have you, by any chance installed a new alternator recently? In my 1970 FSM the standard alternator output is 31 to 37 amps, A/C cars and Heavy Duty uses 41 to 47 amps, and for Fleet vehicles - cop cars, cabs, etc - 48-54 amps (for which Chrysler bypassed the bulkhead connector for that same wire you are having trouble with). These days you get a nice fancy looking alternator and it puts out 90-100 amps, if not more. Just try to get one that put out standard amperage for your 40-50 year old wires. I had to take an old one to a rebuild shop to get it down to 43 amps, after almost burning up my Dart through that circuit after I installed a shiny chrome alternator.
 
I have one issue with high out put alternator theory burning the wiring. And correct me if wrong. The alternator B+ wire goes to the bulkhead plug to the amp gauge and from there it splits to the fuse box, and back out to the battery. The wire in question is the harness plug for the ignition switch? Right? After the fuse box. That would be the “load” side and not the “line” side in the system- after the fuse able link. In other words the damage - in this particular case is from too much draw or an over load of need for electrical amperage and not too much feed from alternator, other wise the wire from the alternator would had melted. In every case when a higher output alternator is used - it can only push so much amperage thru a particular wire. The B+ alternator wire is the restriction, like hooking a garden hose to a fire hydrant vs a 3” fire hose. Same source and same pressure (13.5-14.5v) but limited output (37amps vs 100amps). The wire can handle only the 37amp and looses the rest thru heat. Too much heat and the wire melts.

You are only going to get so much amperage. Also high output regulators in a small body alternator means it can put out say 100amps but for how long? Heat and friction will slow the output. The frame of the alternator can only handle so much current. That’s why the “duty” of the alternator from the factory is rated at 37amps. It can run 37amp output all day and night. Could that alternator put out more- yes. But for how long is the question.

So in theory if a harness is a limited factor. Based on output and draw the next place to check is the bulkhead connector and those connection. Sorry- just trying to prevent a fire else where on my own stuff too. Lol!
 
In other words the damage - in this particular case is from too much draw or an over load of need for electrical amperage and not too much feed from alternator, other wise the wire from the alternator would had melted.
I think your conclusion is correct.

And correct me if wrong. The alternator B+ wire goes to the bulkhead plug to the amp gauge and from there it splits to the fuse box, and back out to the battery. The wire in question is the harness plug for the ignition switch? Right? After the fuse box.
This is not quite correct, but I don't think it effects the scenario.

The alternator B+ wire goes to the bulkhead plug.
Bulkhead plug to the main splice.
From Main splice
------> Feed to ignition switch.
------> Feed to Fuse box
------> Connects to ammeter (Feed from/charge to battery)

Basic 1960s power feed scheme is like this.
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The general feed scheme stays the same in the 70s but with some differences
Obviously with the key switch in the column there's another connector.
'76 A-bodies have externally shunted ammeter and several fusible links.
By '76, if not before, alternator output is split before the bulkhead.
 
Interesting. The 1973 Dodge FSM shows the Dart wiring with optional 60 amp alternator.
The 60 amp alternator output wire was bumped up to 8 gage from 12 gage.
They also ran both feeds through a grommet.
The alternator feed was attached at the ammeter stud. Same location for attaching the optional rear defroster.
The diagram is not clear about whether the standard alternator output wiring was left in place. If so, its a parallel feed.
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The battery recharging load is always a variable.
A low battery given 14.2 volt supply will suck a lot of power if it can.
The standard alternator at idle can't supply that much, especially at low rpm. In that way the wiring was somewhat protected. Keeping the rpm down and watching the ammeter, you could keep the current under control. I've had to do that. It's not a good practice but something might have to do in an emergency.

Charging Battery with Alternator - Warning

As a comparison to normal loads.
Here's some I measured with an inductive clamp meter on my Wagoneer's alternator output line.
Although it has a self generating field, the rest of the loads are very similar to later a-body with electronic ignition, side marker lights and 55/60W headlamps.
Basic running current draw was 3.5 amps - that may or may not include the field draw.
Additional Loads broken out individually:
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Have you, by any chance installed a new alternator recently? In my 1970 FSM the standard alternator output is 31 to 37 amps, A/C cars and Heavy Duty uses 41 to 47 amps, and for Fleet vehicles - cop cars, cabs, etc - 48-54 amps (for which Chrysler bypassed the bulkhead connector for that same wire you are having trouble with). These days you get a nice fancy looking alternator and it puts out 90-100 amps, if not more. Just try to get one that put out standard amperage for your 40-50 year old wires. I had to take an old one to a rebuild shop to get it down to 43 amps, after almost burning up my Dart through that circuit after I installed a shiny chrome alternator.

No, just got the car in January haven't done any changes yet. There is a CD Stereo installed under dash and the power wires to that seemed to be attached via spade connectors on the fuse holder clips- maybe that was drawing too much?Hopefully I can get digging through the wiring this weekend to check things out
 
Thanks everyone for your help and input, wiring is like a different language to me, so I am learning alot!
 
Thanks everyone for your help and input, wiring is like a different language to me, so I am learning alot!
Hopefully our side discussion stayed relevant enough.
Whether the stereo draw could have added to the load on that connector depends on whether it was added to the switched side of the fuse box or the always side of the fuse box. That's what Redfish was getting at. How much it added is another question. If its not turned up to 11 on a big amp its prob not a big load.

I'd check the condition (post 11) and if OK, reassemble and do some voltage drop checks.

What year Duster?
 
Check the positive heavy wire at the bulk head connector. This is a common place for a bad connection to develop and cause a heavy resistance and will get hot and burn the wires up.
 
For what it's worth, I had the same issue with my 73 Sport project. Replaced the ignition switch and the red wire pulled out of that old factory connector when I hooked the new switch connector to it. I decided to do away with it. Bought a Weather-Pack connector, the proper size sleeves and terminals, and replaced both sides of the connector. Worked out great and no worries about future failure.
 
Took the Dart out for a spin today after setting timing, all going well, turn the corner and car shuts off, lost all power. Pull over, reached under dash jostled the ignition switch connector and I was back in business, got home and took a closer look, the large red wire of the ignition switch connector was loose and not seated in the connector properly, connector was burning hot. What is the best way to fix this? Replace switch- connector? Or simply place new terminals on each end of red and reconnect? Thanks!!
Hello, this is an older post but I hope you can help me. my ignition switch connector melted. I've searched the internet for hours but couldn't find a replacement. Can you tell me where I can get a plug like this or even a better one that doesn't melt again?

greetings from Germany
 
Depending on the condition of the the other terminals and your skill, you could change to a different connector.
Keep in mind that one cause of poor connections (that then heat up during use) is the condition of the crimp holding the wire to the metal terminal.
If this is not well made to begin with, or if get gets damaged from vibration and oxidation, then it will have increased resistance. New is not always better, although it can be.

Another cause of heating is extra loads on that wire. Need to know which wire(s) overheated, what year and options, and any modifications made. That may solve future overheating.

To answer you question: We have not found the exact pin terminals and connector housings other than new old stock or used. But several people have found workable products.
See the posts in these two threads

Shanker here tries a molex, and that also links to Thorax's search.
 
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