No power to ignition or dash

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Mark2992

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Hey guys, I have a 69 barracuda that I’m having issues with. I’ve recently switched out the carb for a sniper efi set up. Having high draw for the pump and some fans I installed I have upgraded to the 110amp 1 wire alternator. Way better charging, although after the new alternator install, anytime I would brake or turn on my headlights or even signal I would lose dash lights, stereo would turn off and even my efi screen would shut off. While crawling under the dash tonight I had a loose wire that would have gone to the old alternator hit my frame under the dash and cause some sparks. I then had 0 power to my ignition switch, or lights stereo, or displays. I changed all fuses out and still have no power. I have a switch for my electric rad fans that works fine still and battery is reading proper voltage. Does anyone have suggestions? Thanks
 
Have you upgraded wiring for the bigger alternator? I don’t think the stock wiring will handle that big of an alternator. It is likely that the bulkhead connector is compromised if you are passing that much current through it. Most of these cars came with about 35 amp alternators.

There are many threads on here about upgrading the electrical system for high current accessories and higher current alternators.
 
Mike69cuda said:
Have you upgraded wiring for the bigger alternator? I don’t think the stock wiring will handle that big of an alternator. It is likely that the bulkhead connector is compromised if you are passing that much current through it. Most of these cars came with about 35 amp alternators.

There are many threads on here about upgrading the electrical system for high current accessories and higher current alternators.
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Yes I did upgrade to bigger wire to handle the amperage.
 
Does the alternator current still pass through the bulkhead connector and amp meter, or did you do a bypass?
 
Fusible link could have burned up. I’d start by checking there. There is obviously some discontinuity between the battery and dash harness
 
remytherat said:
Fusible link could have burned up. I’d start by checking there. There is obviously some discontinuity between the battery and dash harness
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Do you know if this could be possible if my fusible link does not connect to anything though? It hangs freely from the bulkhead connector into the engine bay.
 
Mark2992 said:
Do you know if this could be possible if my fusible link does not connect to anything though? It hangs freely from the bulkhead connector into the engine bay.
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If it’s not connected it can’t be the initial problem you are describing. But that itself is a safety concern that should be addressed.
 
The two big wires that go through the bulkhead connector are the feed and return for the amp meter. The dash can be powered up by either one, since they are effectively tied together at the amp meter. It sounds like the fusible link was abandoned and the dash is getting its power through the return side.

If this is the case, as stated above, then there is no fusing on anymore to the main car power circuits and that is a formula for disaster.

Check your bulkhead connector. There are three high current wires that go through it that are often problems:
The amp meter feed
The amp meter return
Ignition power
 
If folks go around adding huge alternators, even 'as small as' 60A or so, WITHOUT at least CHECKING and or repairing the stock wiring, you are GOING to have trouble.

First time I experienced ammeter/ bulkhead connector problems was in the early 70's my 70 440-6 RR. Obviously, "no internet." I ended up drilling out the ammeter terminal holes in the connector, and running paralleled no 12 wires (what I had) through the holes

Those bulkhead connector terminals WERE NEVER up to the task of carrying very much current, and were in fact "on the edge" with 40A or sometimes less.

WHAT YOU NEED to do

If you do not have, wander over to MyMopar.com and get yourself a free service manual. Also go to their wiring section and get one of the aftermarket wiring diagrams which are not as detailed but sometimes easier to follow. I reference them and the service manuals both

THEN read this article on the hows and whys of the ammeter circuit failure


This simple diagram from there shows the idea of the ammeter circuit

amp-ga18.jpg


The main points of failure can be at the ammeter itself, the wire end terminals at the ammeter can fail, and the ammeter itself can fail. This is because the ammeter studs have no brazed/ soldered connection to the internal structure, it is simply a pressure sandwich through the shunt, the insulating washers and the sometimes plastic of the cluster housing. This can get warmed up and then loosen and then you have TROUBLE

EVEN IF you feed the alternator to the battery direct, the big BLACK and big RED ammeter wires are still acting as a parallel path to feed the interior of the car. The ammeter terminals must be jumpered together or the ammeter for sure repaired or checked, and the bulkhead terminals MUST be replaced, checked, or repaird.
 
Mark2992 said:
Hey guys, I have a 69 barracuda that I’m having issues with. I’ve recently switched out the carb for a sniper efi set up. Having high draw for the pump and some fans I installed I have upgraded to the 110amp 1 wire alternator. Way better charging, although after the new alternator install, anytime I would brake or turn on my headlights or even signal I would lose dash lights, stereo would turn off and even my efi screen would shut off. While crawling under the dash tonight I had a loose wire that would have gone to the old alternator hit my frame under the dash and cause some sparks. I then had 0 power to my ignition switch, or lights stereo, or displays. I changed all fuses out and still have no power. I have a switch for my electric rad fans that works fine still and battery is reading proper voltage. Does anyone have suggestions? Thanks
Click to expand...
I appreciate everyone’s very quick replies. Not sure how or when or why, but found my ignition power wire dangling under my dash not hooked to anything. My ignition switch must have been drawing power from somewhere that I don’t know. Ran a quick length of wire from the battery and hooked it up to the ignition switch power wire. Fired the power right on and was able to start the car, I was also not having any of the previous issues with lights and stereo. Now I need to get that fusible link in the circuit to my starter relay and I believe I should be good to go. Again thanks everyone, I love this group
 
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