if you aready have both wires running out of the bulkhead block you are just fine... the black wire from original underdash harness needs to be there to feed the main splice what spreads the power everywhere, so you should get two wires on black side of amm post. Is a must.

Mostly sure you have also the stock black wire running through the bulkhead block and all allong the engine harness up to the alt( so the same two black wires arriving to alt post )... that's fine too.

aftermarket AC box... wondering where are they sourcing it... I hope not from the bat side of the charging system and correctly from an acc source no matter if using a relay, but from alt side of the game. NOTHING must be sourced from batt side of the game with an ammeter in the line.

The blue 16 gauge fuse link is doing nothing if the other side is not arriving to the ammeter. You can remove it and will be safe of a wire hanging around hot without any function. Tape the red section of the engine side wire on forward lighting harness together with the rest of harness just to keep a clean view ( just a suggestion ). ALTHOUGHT you can hook that wire back to the ammeter as mentioned earlier, just that I would suggest get both red wires on engine bay side spliced together into a just one fuse link. As mentioned, will give you more headroom to the charging system being double wired. Don't need to get worried about the bulkhead conections anymore, they are safe with the parallel path. You have at this moment the same setup I have, also on a 74 Charger and I will correct the fuse link setup too, using just one instead two.

now get a 100 amps alt ( which should be to source up to 55 amps iddling if needed ) and enjoy your setup.

sorry once again, I didn't read this before

Either one physically COULD work... however the wire between the starter relay and the batt also feeds the starter motor solenoid through the relay. I don't know if the starter motor solenoid will suck enough power to blow the fuse link. IF NOT ( and I can't tell it really ) that could give me a great idea to link both red wires straight to the starter relay stud, then the single fuse link setup from there to feed the batt wire. Would make easier this splice job of the parallel wiring system.

I can't tell how much load sucks the stater solenoid by itself though to be hold by a 14 gauge wire. Maybe not specially if for some reason needs to get cranking several times or for long time. Maybe that's the reason why it's ( if we think the load running from batt ) after the relay and not before, but we are talking stock setup uses a 16 gauge fuse link, not 14.

Does somebody knows how much amps sucks the starter motor solenoid ? 20? 30? 40?

If your sketch is what you want to do, that will work if
the ammeter is good.
As Nacho wrote, remove the fusible link going nowhere. No need for a hot wire that is not terminated at something.

What I see in the photo as you found the wires is one with a ring terminal attached to the back of the ammeter. From what you wrote above, the wire from alternator power connects to the red from starter relay. What you call 'dash harness' we are assuming is a heavy wire to the main junction. (This is usually a welded splice). Attached is what I think the "as found" situation is.

Are you reinstalling the A/C? What year and model?

Thanks for the drawing. I'm not re-installing the Mopar underdash A/C unit. The hoses were cut off in the engine compartment. They cut the dash frame to install it back in the 70s. They routed flexible hoses to the dash vents they had cut in the dash frame and stuffed it all up under the dash. They had to cut the glove box down to 1/3 of it's original depth. Going back stock for now but may install a Classic Air or other brand under dash unit soon. The holes are already in the cowl for the hoses. There's the option to use the unused wiring for it. Since the dash frame is out, now is the time to decide on the a/c seems like. The original plan was to use the Charger for nice weather long trips, so a/c would be needed. Now that we have a 2015 Shaker Challenger, it's hard to beat the modern conveniences for travel. We've used it on several trips over 1500 miles and it's nice.
Again, thanks.
Terry

I'm understanding he got two black wires running to amm post, the original and the bulkhead bypass and really the red wire bypass running correctly to ammeter. Just the original red one is isolated and going nowhere.

I think I'm looking at these two parallel paths on the second pic he posted



So if Is like I think, he is correctly set.

Nacho. Yes I see. I'm not sure.
Lets assume the hanging wires taped together are the pair through a grommet. Then you are correct.

In the next photo there is only one wire on the ammeter. That seems to be the original to the main splice.


So, the best connection will be to remove the nuts on the ammeter posts and attach the hanging wires. If the ammeter is OK, it can be put into the circuit.
Then the only question is what happened to the original alternator output wire? If the connection is OK, like you write, it can be left in parallel. If not, it should removed such that there is no hot wire floating around. Same as done on the battery side.

Well it seems the cluster and harness are out of the car together ( I can see the firewall hole for the bulkhead ), while parallel paths are still on car since they didn't get a quick disconect plug, and still on firewall on that visible grommet.

The black wire can't be disconected from amm post since the ammeter post needs to be used as juntion to get together the parallel path and the main splice to be sourced from alt. Diff story is to know what we do have on engine bay side, if stock alt wire is being used or not.

if ( same as the red one ) is not being used, better remove it to not keep a hot wire hanging around. On red wire case, just remove the 16 gauge fuse link is enough.

if bulkhead paths are still healthy on both, red and black, I DON'T SEE a reason to remove them. I'll keep using those. BUT once again, just using ONE fuse link... the 14 gauge one, so both reds spliced into just one fuse link.

My 74 got the AC harness running out of the bulkhead and is on that way from factory in every 74 with AC due the lack of cavities left on bulkhead once the interlock starting system bypass was added. So ON MY CAR I used this same grommet to run together the AC harness and parallel charging paths, just enlarging the AC grommet hole to fit all 4 wires through the rubber. I didn't want to cut my firewall for this just to run couple of wires whcih are not stock. If this car got factory AC ( which is my understanding ) the parallel paths are running throught that same factory AC harness grommet, just AC harness is not there. I think to recall the AC harness grommet is located just right there like the one shown on pic

In 74 the tach when optioned run by the ONLY cavity left by that year on bulkhead at NSS plug section

In previous years, the AC harness used the blower source ( also for heater ) at the only NSS cavity left and the compressor clutch at the only engine harness cavity left, while as far I recall tach run with a grommet... so it was reversed than 74s

Mattax, yes your "As Found" drawing is correct as it now sits. The a/c unit that was in car when I bought it was installed by the dealer and was kind of an under dash unit but used vents in dash frame for the cold air. I'm not reinstalling this unit but may go with an under dash unit like from Classic Air or similar. In the pic showing the back of gauges, you can see the original red wire not used now. I may need it if I install an aftermarket a/c unit. If I don't , I can remove it or use as a parallel circuit with a tie in to the bulkhead block bypass wire as Nacho suggested. Thanks for your assistance. The bypass wire coming through the bulkhead was dealer installed also from what I can tell and the grommet is the one you see in pic near steering column. Thanks. again.

Sorry a little off topic, but I couldn't resist.
Oh, resistance is somewhat in line with the topic.
Not really though.





That's just toooo funny.

Cheers Nacho.

if is like the LAST "as you found" diagram ( because he posted two "as you found" diagrams LOL ), you are set on the parallel path ready for higher amperage setup like I allways suggest. Just reinstall it back like it was.

How it does look the bulkhead ? some burnt spot ?

I think already have explained enough what to do with the stock red wire going through the bulkhead, but once again:

-No reason to remove it if bulkhead paths are in nice conditions. Is posible and even healthy keep it in use BUT splice both reds into one fuse link to Starter relay, the 14 gauge one

or

-Remove the blue fuse link. No reason to have it there being feeded and sourcing to nowhere on the other side, having unnecesarilly a hot spot hanging around without any use.


get a 80 or even better a 100 amps alt and your car will be happiest than never before

just being honored to the thruth

cheers

Nothing wrong with the sport/game, but with the name LOL... just like the Chagnum... nice car, wrong name

Can't wait to get together with friends for a Green Bay Packer egg arm game and toss this out there.
It'll go over big time.

I still dunno why you call Soccer to the Football. THE COMPLETE WORLD call it Football, but you guys LOL.

even in Spanish

Foot--- Pie
Ball--- Balón, pelota

so then... Balompié in spanish ( it gets M because an ortographic rule in spanish says before P and B letters any word must get M and never an N )

Althought tipically called Fútbol just as a "spanishing" of the Football english world

Nacho, You have been extremely helpful to the OP with his severe electrical disaster (& much appreciated) so what we are going to do is give you a free (hail mary) pass (just this one time) on your other issue (& that is a football term).