72 Ignition Bulkhead - Big Red wire? Litle yellow wire?

[Daytona Guy]

ON the 72  ignition bulkhead...where does the big red wire go? What does it do? What about the little yellow wire? Where does it do and what does it do?

On the engine bulkhead, where does the big gray wire, that appears to be a fuseble soft wire, does it go?

Any skamatic?

[Nacho-RT74]

you mean the front lighning harness ? That harness has a heavy red wire that runs directly to amm stud labeled as RED, but first is bolted on to starter relay stud coming from batt. Between Stud and the bulkhead is a fuse link, normally blue colored, and then red again on regular wire up to plug.

Yellow wire is a direct line ( no splice or anykind of intermediate plug or link ) from ignition swithc up to starter relay. Is the input signal to Relay to give power to Starter Motor.

Big Gray wire on engine harness... I don't remember anykind of gray wire on any engine bay harness, even I now some aftermarket and repro harnesses use that color to Oil sender... however on my car is somekind of tan, not gray ( is the original wire ). BUT think electrical net is made in Venezuela, not imported ( Chargers were assemblied here with some parts also made in here with original USA castes )

[Daytona Guy]

you mean the front lighning harness ? That harness has a heavy red wire that runs directly to amm stud labeled as RED, but first is bolted on to starter relay stud coming from batt. Between Stud and the bulkhead is a fuse link, normally blue colored, and then red again on regular wire up to plug.

Yellow wire is a direct line ( no splice or anykind of intermediate plug or link ) from ignition swithc up to starter relay. Is the input signal to Relay to give power to Starter Motor.

Big Gray wire on engine harness... I don't remember anykind of gray wire on any engine bay harness, even I now some aftermarket and repro harnesses use that color to Oil sender... however on my car is somekind of tan, not gray ( is the original wire ). BUT think electrical net is made in Venezuela, not imported ( Chargers were assemblied here with some parts also made in here with original USA castes )

Thank you. That is different than my 70. On the engine harness - The long dark gray, black, dark green or dark brown or whatever color an old wire becomes, it is long and it is a very soft and flexible wire, like the fusible wires are made with, and it has a, for the lack of an intelligent description, a female black speaker type connection on the end. On my 70 I have a fusible wire that is short and soft that says "fuse" on it...does this 72 have a wire coming out of the bullhead that is fusible that goes to the starter relay?

[Nacho-RT74]

wait untill I post pics on board to make a better description... I'll open a new thread about 3rd gen wiring making specs and differences between all 71-72-73 and 74 differences I have noticed allong the years

[71_deputy]

Only two gray wires in the engine bay- one for the tach off the - coil- it is a ring terminal
other is off the harness- for the oil sending unit!

John Mac

[Daytona Guy]

What about the air conditioning pump?

[Nacho-RT74]

Air conditioning copressor is blue, and suposelly on 71 and 72 is on same tranny harness plug, with also a green wire that feeds the blower.

will be a next diagram.

Jhon, I though tach is supposelly green traced yellow... I could made a mistake then on that since got confuse on color code ( GY )... I think will need to edit the diagram.

[Daytona Guy]

Air conditioning compressor is blue, and supposedly on 71 and 72 is on same tranny harness plug, with also a green wire that feeds the blower.

That is it. Mine is a flat black or dark gray, but what you describe is it. But my compressor pump wire comes out of the engine bulkhead and then joins the green trany harness with the green wire that apparently connects to the blower/fan motor? My color was most likely changed - Thanks

[Nacho-RT74]

compressor wire goes to pressure switch at dryer firts, then to compressor... I don't think that is the Compressor wire, but who knows.

On 74 and I think also 73s, compressor and blower wires goes throught firewall with a grommet because tranny harness sends a NSS ground signal to seatbelts system to the cab ( warning system ) lefting just one cavity emptied, however since the regular setups left some cavities emptied all around, then anykind of setup could be used to the extra accesories.

On 74 in fact all tranny harness plug is full with also an extra signal from fellow wire to starter relay, spliced from inside the cab to reset interlock button

Maybe assembly plant could use the empty cavity on engine harness where there is not tach to the compressor, and then if NSS ground signal is sending to cab to seatbelts warning system, then the other emptied cavity just directly to blower.

Is easy to check... on back of bulkhead, AC harness is taped on a separated harness from the rest of underdash, and arrives to bulkhead with the blue and green wires. No matter the cavity, they are taped together allong the underdash separatelly from the main harness.

What I want to mean is that A/C harness is linked just on two or three points with the rest of underdash harness with terminals on plugs, so removing terminals from plugs you get a separated harness.