Kai2006
New Member
Thanks! It seems that this black wire goes directly to the bulkhead connector. But how is it suppliee with 12v?
1969 Plymouth Fury, Starting/Ignition or electric issue?
- Thread starter Kai2006
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3175375
Senior Member
I would have to check the schematic. I can do that later today.
You should have a factory service manual and the vehicle electrical diagrams are in there.
3175375
Senior Member
FYI - I have a couple of the largest diagrams that these guys offer and they are helpful:
ClassicCarWiring.Com Home of the original color laminated diagrams
Kai2006
New Member
Ok thanks I have a good wiring diagram, but I still wonder if there is a direct connection between the battery and the alternator. As said we meassure 3v at the alternator but only when alle connectors are plugged in in the bulkhead. So it seems this feed runs through the car to the alternator?
Yes, there should be 12 volts at this point. Follow it back to the bulkhead disconnect at the firewall and it goes to #16 on that plug.
From there, under the dash, it goes up to the ammeter. The feed wire on the ammeter is red and that runs to #28 on the plug. Once that goes through the bulkhead connector it runs to the starter relay then through a fusible link directly to the battery.
So, I would start at the battery and the fusible link. How did you check the fusible link? You can't tell if it's OK by just looking at it.
Yes, direct connection through the ammeter from the battery to the alternator. And yes, the connectors would have to be plugged in or there's no connections.
Kai2006
New Member
Hi john, thank you. We checked the fusible link with a Fluke. And we meassure 12v before and after the fusible link. Also on #28 we have 12v. But not on #16; here we have only 3v.
3175375
Senior Member
Inspect the bulkhead connections and the connection to and from the ammeter.
Kai2006
New Member
We have found the ammeter and connected the two wires on it together. But unfortunately…..smoke! So quickly disconnected ground of the battery. Could be that we touched something on the steering column as half of the dash is dismounted now. But how to proceed wisely now?
A partially burnt-out fusible link can still show 12 volts, but it won't pass enough current through it to do the job.
I would say that you have to figure out if you've shorted it. I will bet you have. Either that, or the ammeter was already burnt from a short.
I wouldn't connect any power to anything until you check for shorts.
3175375
Senior Member
You are going to have to trace that hot wire all the way back to the bulkhead connection. You may want to start by disconnecting the bulkhead connections and look on both sides (engine bay and cabin).
You are going to have to be diligent in this.
You’ll find it!
Gerald Morris
Senior Member
If you got smoke only when you directly connected the ammeter leads together, then there is an excellent probability your ammeter WAS BURNT OUT TO START WITH! THIS will prevent current from passing through it, which will block most of the accessories under your dash. Read up on the "ammeter bypass." Check the resistance of that ammeter. I suspect its HIGH if not infinite by now.
REPLACE the fusible link. This can be done by purchasing generic fusible link wire of the proper size, which likely will be #14 AWG. Fusible link wires are customarily 2 AWG sizes smaller than the circuit they protect. To wit: if you have a #10 AWG wire, the fusible link will be 2 even sizes smaller; #14. Be sure and find what wires you smoked. Your short circuit will be connected to those. Of course, you may have just smoked the fusible link. They do that when they go, but it isn't too much.
Those ammeters are nothing BUT trouble! Get a voltmeter and attach it to the junction you make with the red ad black wires which formerly fed that ammeter.
One of those wires should have been fed by the fusible link, while the other should go pretty directly to the alternator. I feed my alternator directly to my battery, with a fusible link, then run my battery through the firewall to the junction of the ammeter wires. They act as parallel conductors thus from that feed, feeding everything! You add one additional fusible link, and eliminate a major electrical failure point by eliminating the ammeter.
I also upgrade my feed to #8 AWG, using #12 AWG fusible link wire, six inches. The two #10 wires formerly in series through the firestarter (ammeter) as I said, divide the current in approximate parallel fashion.
Whatever else is wrong with your wiring, this SHOULD help.
“Firestarter ammeter”? The myth continues. Well for that matter, there really isn’t anything in this post I can agree with except maybe “Read up on the "ammeter bypass."”, or the big problem with the ammeter/shunt wire by-pass. Better hope you never experience a short in any of that stock un-fused wiring with all these parallel fusible links and wire runs. Added voltmeters need switched power, can’t use the unswitched ammeter leads for a voltmeter. Curious, just how does one of these ammeters “burnout” when operated as it was designed, good connections, and within its design limits?
Gerald Morris
Senior Member
Well, I can see that the CONCEPT of TWO WHOLE FUSIBLE LINKS BLOWS YOUR BRAIN FUSE, so if I thought you could learn anything, I would proceed in monosyllables.
Rather childish response.
Indeed, someone with an apparent electrician background, suggesting wiring circuit protection devices (fusible links in this case) in parallel, exposing all stock unfused wiring to more battery current potential than it can handle safely in the event of a short, does “blow my brain fuse”. Would have to agree as well, I don’t think I could learn anything from you, no mater your diction.
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