Alternator gauge just went on vacation...MMMM!

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woodwiz

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Just went out and fired her up and when i opened the door and sat down as usual to start her with the door open(love that sound)! I always notice the alternator gauge moving +or- and when i shut down the gauge was pegged completly -. Best trouble shooting ideas would be helpful....Thanks in advance!
 
Back on the alternator gauge snafu. As usual I used to notice when I opened the door that the alternator gauge would move to the discharge side. But as I said in the first post it appears all the way pegged to the neg. side and stays there. Yesterday got in and turned the key to ign. and the gauge moved to -40 then turnoff and back on and it bounced back there again and start and run and nothing. Help! Sounds like a ghost in my cluster.
 
Ammeter is pretty much independent of the rest of the cluster. Have you looked at the connections on the gauge? Loose, burnt??
 
Sounds like the amp gauge is grounding out. I would make sure that the neg battery terminal is removed when parking to prevent a melt down. Or even better, get a disconnect switch for the battery.
 
The insulating board that insulates the terminals will deteriorate and the studs can come loose also do to electrical heat
 
Thanks to you all for the info. I will check all of that stuff. The pics show the gauge needle pegged full negative whether running or not. I know that I have some protection from it burning if that were to happen 1.Fuseable link
2.Halon fire extinguisher which I hope to never use.
Like to keep all the stock gauges working but maybe someday a Dakota digital dash$$$$
 
What are the culprits of this dead short? I have heard that if the alternator takes a dump internally that i would not know it till the fuseable link started smoking or fire which while driving has not done that. Also if the alternator went i would not be able to drive it as far as i have.
Like you all have said to chk.the connections on the back for loose or god forbid burntness....more opinions please!!
 
the wires from the battery go to the amp gage and no fuse link . look at the wire diagram it shows this. google it and see the burnt cars very sad.
 
I have a fuse link something my hot rod shop guy told me about after I bought the car. I was totally unaware of and he said it will save these old mopars from burning to the ground.
That’s why I carry an extra fuse link and a Halon extinguisher. Now I got under the dash….that was pure torture,but the red & purple wires going to it don’t look burnt but they appeared to seem connected but loose. Is their a way to take the gauge out of the whole equation until I pull the dash for a deeper look? Oh came up from trying to tighten the 2 little studs on the gauge and put neg.terminal back on and the gauge popped up to -20 I then turned on the ignition and it dropped past-40 to the peg. Might it just be those two connections?
 
You don't need more opinions, you really need to take the cluster out and investigate. Sometimes when trying to tighten the nuts the studs will turn in the ammeter base causing other problems. You could remove both wires and bolt them together, wrapping heavily in tape for the short term, but you are better off fixing the problem. Most likely the gauge is fine, just needs some care. The ammeter needle moves to the negative side when pressing the brake pedal with engine off because you are illuminating the brake lights, nothing strange about that.
 
I heard that is what you do with those wires when upgrading to the digital dash,but that may be a ways off. So the nuts on the back of the gauge don’t seem to tighten,but it’s real tuff to get a small wrench on them as it is.
Hence a real good reason to pull it all out. Here’s maybe something of interest,started her up and the gauge pegged all the way to +side and stayed there bouncing a little when I applied the brake. Shut down and it stayed pegged + until I applied the brake pedal and then back to all- side
Went through the process again and now as you can see the needle is neutral as it used to be before all this started.
If I tape the 2wires together temporarily has my fire risk gone down at all??
Thanks you guys in advance!!
Just can’t lose my babybird.

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I would check out the ground on the alternator and make sure it is well grounded. Do you have the comp. voltage gauge under your dash as most of us do? How does it read. Those terminals on the amp meter are not the best. Loose wires are not a good thing. I would replace it if you can with a new one. After all it is over 50 years' old.
 
Hey Russ, When I worked my way under the dash yesterday and checked out those 2 connections on the gauge they really wouldn’t tighten up but as a pair their seems to be a little backing plate strip of metal connecting the two and that seem to move around a little.
While the the ignition was on i went back under for a look to see if their was any hot wires or smoke etc. Did notice that if I moved the back of the gauge their was this very small little spark,it might be due to that loose gauge connectio…who knows how long that may have been going on. Will the fuse link protect that circuit in the event this gauge really goes sideways. Yes to a new gauge,but like you said gotta pull that dash out and hopefully test them all and apply dilectric grease to all connection. Also I’m only seeing 2 wires coming off the alternato,is there a 3rd for ground or would it already be ground. Overall I was thinking this gauge worked fine a month ago,so with the intemittent operation the gauge might be good.
Thanks for the help,without it I’m chasing my tail!
 
The gauge is pretty robust and most likely good, the issue is with the connections. Without load on the wires, they probably won't be to warm, add load to a loose connection and I'm sure the wires will get hot. Its time to take cluster out, get the gauge in your hand, post some pictures and we'll help you repair. I would not worry about anything else in the circuit until you fix the gauge/wires. Will the fuse link blow before the car burns to the ground? Maybe/Maybe not.
 
The alternator on this bird is stock and I have 2 wire connections as in the pics one black and one gray also their are several green (I’m assuming ground wires that come out of the cluster of wires to the alternator and temp sending unit and horn. There are 2 green ground wires not connected to anything not sure why. Been like that since I got it. The insulators on the gauge that 69hemibeep suggested,are they cardboard?
 
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