Ammeter wires oh so hot!

woodwiz

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Brought this up awhile back,but I would like to revisit the problem.
Ammeter took a dump a while back so on advice of some forum folks I spliced both wires together and currently they are in an accessible spot hanging under the dash. I can reach over on a drive and can barely touch them because they are very hot. This is noticeable at higher than idle speed. That current running through the wires generated by the raised rpm of the alternator has left me scratching my head. I can’t figure this out. I pulled each one of my harnesses on the firewall bulkhead and they did not look burnt or signs of melting. So I gave them a small wire brush cleaning and applied some dielectric grease and all went back just fine. Also put a voltage meter on the battery when idling and unless I don’t have the meter set right the needle pegs all the way past 15v…any clues,did I hook up wrong? I have a new ammeter gauge,should I just drop the gauge cluster and hookup the new gauge and all will be right in the Mopar world or is there a bigger problem?
Sorry to blab on about this but I’m not comfortable driving the car with wires running close to lava temps.
I did also hear that an additional wire run from the back of the alternator to an inline fuse link attached to the starter relay….good or bad idea? Suppose to take some of the load off the circuit!
Thanks for any help guys!
 

V.R.D

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that second connector of the bulk head is toast you will need to replace it and the wires will need repaired / better to replace the under dash harness and bulk head.
 

woodwiz

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I was surprised to see the condition of these harnesses. The first one was pretty clean. As you saw the second one is questionable,but you saw it after some cleaning and application of some dielectric grease. The second harness does appear to have a loose (female)connector and I will have to verify that it is at least still connected to its wire. The wires don’t seam to be original and at some point before me this car was restored,but I don’t know if all of these components were part of that.
Are the under dash harness plugs pretty much mirror image of these? Plugged it all back together and everything seems to work. Is changing out the harnesses a plug and play as far as the engine bay is concerned.? Would love to gut the wiring in the whole car just for peace of mind at least.
 

V.R.D

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a car more than 50 years old the electric harness builds resistance witch is what melted the bulk head connecter . it needs replaced you can get a complete new harness m&h is one of the makers year one is a seller of this it should be plug and play. i recommend you get the service manual and read it 5 to 6 times for your repair and the wiring diagram and trace wires while it is still tougher to get familiar with it.
 

woodwiz

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So hard to tell how old these are. They may have been done 20+yrs ago but who knows. I looked at that harness again this morning and cleaned off the overdue of electric grease and I don’t see any melting or burning effects,but like you say anything 50+yes old is not new! Do you think I should just replace the other harnesses (2) as well?
 

woodwiz

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Here is the middle bulkhead harness connection. Those 2 connectors in the base look different,why? Not totally sure.
But the one on the far right connects to the plug that has the fuse link that was on the car when I got it. The second connector which looks like it’s brass..maybe replaced or worked itself loose I believe is from the alternator. The rest look good…solid connections.
Would the one on the far right that connects to the fuse link side go inside and connect to the ammeter?
 

V.R.D

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i have seen this many times it is up to you on what to do next. look at the wiring diagram.
 

woodwiz

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Just looked at the wiring diagram and traced that deformed right side connection from the ammeter to this connection with the fuse link.
Got warm there at some point or still does. The old connections on the back of the ammeter when hooked up I believe the insulators on the studs and the loose connection was intermittently sparking. I took both of those wires and bypassed the gauge and spliced them together (temporarily). Would that cause them to get hot as I have found out by grabbing them on a drive? Reinstalling a new ammeter cool things down a little and the bulkhead harness??
Thanks!
 

Carl Ray

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No, hooking up a working Ammeter will not fix the problem. That bulkhead needs addressed. M&H replacement harnesses are pretty much exact OEM and easy to install.
 

woodwiz

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Ordering as we speak…just because!!!
Amazing it has gotten this far!
Lucky me!!!
Thanks for the help!!!

59F50455-6CD3-4B5A-8FAE-45DEAD5E9AB9.jpeg
 

Carl Ray

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I would get the engine harness at the same time. They are somewhat specific on ignition type. I would also pull the cluster, it will be easier to install the new harness (because you can see more) and you can better inspect the Ammeter. I prefer having a functioning Ammeter so it needs inspected. I have the insulators if you need them. I'd also consider running a parallel path to the Ammeter from the Alternator to reduce bit of load on the bulkhead.
 

woodwiz

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I’m going to start at the worst place..under dash/bulkhead harness and get the engine harness down the road-no pun intended! Feeling very lucky today my expert electronics buddy came over and we agreed that this car could have burnt up at any moment. So he looked in his shop and lo and behold he has a harness from M&H that’s made for this car. I guess Classic Ind. they are on an unknown back order…again lucky! Also I have a brand new ammeter gauge that will go back in as well. Could I trouble you for more info on the extra alternator wire to the ammeter!
Thanks so much for your input!
 

69hemibeep

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Like said above inspect the ammeter the fiber board(forgot what its called) and studs will cook and get loose. The board is the insulation at the meter
 

woodwiz

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That’s where this all began at the loose,burnt wires and broken insulators around the ammeter studs. That has been disconnected awhile ago. New harnesses on the way and I have a new ammeter going in as well. Checking everything else in the cluster as well.
 

Russ Hood

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I just replaced my engine harness and under the dash harness. I had the same issues. You will a happy man when this is done.
 

Russ69Runner

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New wiring is a must with these old cars. After looking at your bulkhead connector it tells the story. Tired wiring and connections. I replace all the wiring in the restoring process best thing you can do. :drinks:
 

woodwiz

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All these 50yr old muscle cars should have new wiring or at least look and check it out to find potential problems. Someone said that a lot of these cars wound up getting new alternators with higher amp output 75+. Not sure what I have hope it’s the stock 60amp. Higher amps and thinner wires lead to heat issues. Is it conceivable that after all is fixed and connected that those 2-wires connected to the ammeter gauge will still get a little warm?
 
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