No power anywhere......

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spacewelder

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Hey yall, so about a week ago I put in a new 90 amp alternator in my 74 318 swinger with MSD 6a. Was running fine and doing some test to see if my stereo was draining power and went to start the car again and had no power to the inside of the car. All grounds, connections and fuses check out. I'm kinda thinking it's the ingnition switxh, but not totally positive. I had to hot wire the car at the MSD just to get it home. Any ideas? I already checked voltage At the fuse box and had no power. Anything helps
 
I had similar issues that tuened out to be a burnt terminal on the bulkhead connector. The main feed that powers everything.
 
We checked all the connections at the bulk head and they were spotless and making good connection
 
Please read this article:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

...........And pay particular attention to the diagram on that page:

amp-ga18.jpg


This diagram gives a good simplified view of main power distribution. You have several "main" failure points "somewhat" in order of most likely:

FUSE LINK. This goes from the starter relay stud to the bulkhead connector

BULKHEAD CONNECTOR. If you have power there, you might NOT have power on the INSIDE half of the connector.

AMMETER. Notice that power goes from the bulkhead connector to the ammeter. Sometimes those wire connections fail, or the ammeter itself.

WELDED SPLICE

This is rare, but it does and has happened. This is in the BLACK ammeter wire a few inches from the ammeter, under the dash. IF YOU have power at the ammeter BUT are losing it somewhere else, this may have failed


Check the "easy" places first

You have headlights? Yes? No?

If no, check fuse link, bulkhead connector (red wire) and ammeter.
 
get a multi meter or test light and follow the power . but like said it is usually bulk head related .
 
I checkSo I checked power at fusible link and was at 12v. Check both sides of bulkhead and had 12v. Had no power going to ammeter. So is it losing power between bulkhead and ammeter or is it just the ammeter
 
Either you made a mistake in measurements, and "it's the bulkhead" or it's right at the ammeter

Example......I've seen the ammeter eyelet terminals fail

Once again, review the MAD diagram. This is simplified, but yet fairly accurate. A "large red" wire connects through the bulkhead terminals. The inside half of that goes right to the ammeter.

If you have not done so, it's time to disconnect the bulhead connector(s) and inspect them carefully.
 
Scratch that. My voltage meter was broken. Had power to the ammeter. Anyone know how to check the ignition switch to see if that's the problem. I can't seem to locate it underneath the steering column.
 
Don't discount the possibility that your testing has "wiggled" and "made" a bad connection.

You say "no power anywhere" we need details on this

Does "everything" actually "not work"?

Headlights?

Brake lights?

Dome lights?

ONCE AGAIN refer to the MAD diagram

Notice that power goes THROUGH the ammeter to the WELDED SPLICE and splits off from there to

headlights

ignition switch

fuse panel "hot" buss

and a couple of other things in some years

You have a service manual?
 
No power to headlights, brake lights, Done lights, etc. like I said I was able to get it hot wired. I do have power to the fusible link, both bulk heads and the ammeter. if what I'm understanding from the diagram is correct, it says that power goes from fusible link, to the bulkhead, to the ammeter, branches to the lights, ignition and fuse box, then through another bulk head to the alternator. I have power at the alternator. So that's why I'm assuming it's the ignition switch. I do have a service manual and I'm not really understanding the ignition switch info.
 
Nope, not ignition switch.

It's why I asked "what doesn't work."

At this point I would suspect the BLACK connection right at the ammeter, that is the wire end itself OR the "welded splice."

At this point problably need to yank the cluster out of there

Be absolutely certain you have power on both studs of the ammeter. If you do it's one or the other of the above.


So far as your service manual, here's an alternative. These diagrams are not always accurate, and don't always show all connectors and plugs. But they "can be" easier to follow.

http://www.mymopar.com/index.php?pid=31

These two

http://www.mymopar.com/downloads/1974/74ValiantA.jpg

http://www.mymopar.com/downloads/1974/74ValiantB.jpg

Start with diagram "A" and find "J" in the bulkhead connector. This is the HUGE thick labled RED wire going off the right of the page. This represents the INTERIOR side of the bulkhead.

Now go to diagram "B". This is simply the way they are "printed."

Find that huge RED coming in at the left of the page, follow it up, through the ammter. This is battery power coming TO the ammeter

So at this point you have come from battery---fuse link---bulkhead connector----red wire---to ammeter---through ammeter---out on the BLACK wire---and off to the left of the page

Now go back to diagram "A"

Find the huge BLACK coming in at the right of the page, and follow to "P" of the bulkhead connector. this contiues out in the engine bay to the ALTERNATOR

Now backtrack that black just past coming in at the right of the page. That splice you see there is the "welded splice." This splits off to feed

headlights --no fuse the light switch has a breaker

hot feed to the fuse panel

and feeds off "large black" to the ignition switch going TO the switch

To repeat one last time, this is why the MAD diagram is so cool......it shows in one small diagram all this "crap" LOL
 
I know for sure it isn't the ammeter. So will the welded splice still give power to the alternator even if that's the problem??
 
"It could"

So let's review so make sure I know "whut"

You say you have power to the ammeter AND at the alternator output stud?

And the headlights, dome lights, brake lights don't work? Nothing on the ignition switch works?

It HAS to be the "welded splice" I bet

Drop the column down pull the cluster. Untape the harness starting at the black ammeter, and look for the splice.
 
That's correct. Ammeter is powered and so is alternator. I'll check that splice tomorrow. What should I be checking for at the splice?
 
You will see. Just look at it. If it's broken, you can pull the wires apart or at least move em. When you get the harness untaped, it will be "in there" If that is it, this will be about the 10th one I've heard of in my lifetime. I found the first in about 1971 on a friend's 69 RR

Might pay to double ---tripple check your meter LOL. Make sure it's grounded. The fuse panel has two buses. One is hot and should be hot at all times. The other is fed from the accessory side of the ignition switch. If there is NO power anywhere in the fuse panel, then you are looking in the right spot
 
So I double checked everything and it's still the same as yesterday. Power to bulkhead, ammeter and the alternator. Just checked the welded splice and it's getting power to it. Do I need to separate all the wires and check them individually? I'm just trying to understand how it could have power at the splice but not at the lights, fuses, or the ignition switch.
 
I don't either. What it amounts to, is about a foot of wire to each. Make sure you are not getting fooled by connectors. "I've been known" to stick pins into wiring through the insulation.

If you provided accurate details, and it seems "as if" then you have to be right in the area.......ammeter.........splice..........that immediate harness and branch wiring

Wiggle the living you-know-what out of it.
 
So I triple checked the fuse box and the light switch for power and they both have 12v. No why wouldn't the be working?
 
Check them with a load that is "turned on?" You may have missed something if that's the case

"Let's say" the bulkhead connector is the culprit, but it's intermittent and make / no make. Your meter does not draw much current. You might check at the ammeter and have power WITH NOTHING turned on. But as soon as you turn anything on, lights, ignition, the connection "breaks" and no power.

Tell ya, LOL this "troubleshoot by remote control" isn't always easy
 
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