Wiring Diagram w/ Values on It?

[archlab]

Just Curious, does anyone have (or know of a link for..) a wiring diagram
(specifically a 72-76, or equivalent A-Body model) that shows the Values on the diagram (i.e- what the Voltages, Resistances, etc for each wire/component/switch/etc. should read when testing w/ a M/Meter).

For example, it would be a real time-saver to have a little chart pointing to each wire on the Ignition Switch, then have it correspond to say:
a) 'Key Off', b) 'Start', c) 'Run'.

I know this would be a helluva tedious undertaking, but it just seems that the original manuals (& their super ambiguous engineers) should've done this exercise about 40-50 years back. However, that old-school bull-headed tech mentality prevented the creation of diagrams that don't require constant page-flippin' & referencing which is not suited for actual work in a shop (maybe on a drafting table, while juggling a slide rule...by guys wearing lab-coats, geesh...lab coat-wearing pencil necked geeks)

So, besides my rant, has anyone seen something like this?

 

[slantsixdan]

Just Curious, does anyone have (or know of a link for..) a wiring diagram
(specifically a 72-76, or equivalent A-Body model) that shows the Values on the diagram (i.e- what the Voltages, Resistances, etc for each wire/component/switch/etc. should read when testing w/ a M/Meter).

1. Each year is different. "72-76 or equivalent A-body" is not "specific".

2. No diagram exists such as you describe.

that old-school bull-headed tech mentality prevented the creation of diagrams that require constant page-flippin' & referencing not suited for actual work in a shop

Bulk wrap. You just have to know what you're doing. If you don't know what you're doing, you don't need a diagram crapped up with a zillion little notes and arrows and numbers and values and asterisks, you need some education.

An excellent start to the necessary education will be for you to get the Stockel and Petersen books described in this thread.

 

[archlab]

I stipulate the need for more eduKashin....but I'd like to not have to go back -n- forth between chapters in manuals so much. Plus, in our heat/humidity, my damn glasses ("Yes sir...I damn thee..."), get so fogged up that I can't read the tiny print on the diagrams while I'm tracing. I know, I know, I need to move somewhewre w/ decent weather, like say the Pacific NW. OK, ya happy now!??! Dangit.

Sorry to wrangle any Old Skooled nerves, but I'm not a full-time Electrician, so a lil' User Friendliness in the diagrams would help get rid of guys like me faster....

Anyway, thanks for the references (& all the other info I've 'stolen' from you guys' posts over the years).

 

[67Dart273]

Arch what year IS your car, to start with

Mopar ignition switches, and the basics of power to the ignition, the headlight switch, the ammeter circuit was very very similar for years and YEARS. The differences start when you get into the later models with smog doo dads, and options like the console and A/C and the dreaded 'seatbelt interlock.'

And actually, the diagrams ain't that bad until the mess of '74, and I'll agree, THOSE are a hell of a mess.


Basically the IGN switch goes like this:

You come in from the battery from the fuse link on the red wire, to the ammter

The other ammeter wire, black, goes out to the alternator output

ON THAT black wire, under the dash, is the "in harness splice" which is a factory welded splice and branches off to supply:

The fuse box hot buss

The headlight (only) power, with a breaker in/ on the switch. Tail/ park comes off a fuse

main power to the IGN switch

On some models the wiper switch, with it's own breaker

From the IGN switch you have:

ACC power back to the switched buss in the fuse box, hot in run or acc

"ignition run", or "IGN1", traditionally "dark blue" feeds power to the instrument cluster and warning light(s) and out through the bulkhead where it feeds

ignition and regulator up through 69

70/ later, feeds alternator field (blue), electric choke if used, some smog doo dads if present, such as idle solenoid (sixpack) and distributor retard solenoid on some models

Then you have

"start" traditionally yellow, from the switch, through the bulkhead, to the start relay

"bypass" or "IGN2" from the switch, out through the bulkhead, to the coil + side of the ballast

NONE OF THIS IS FUSED, and is very poorly "protected" by the fuse link

 

[BillGrissom]

Measuring the resistance of wires would be extremely difficult since they have very little resistance. You would need to use a special "4 wire" multimeter. It is also not easy to get at both ends of most wires since far apart. The wiring diagrams detail the color and gage of each wire, which helps a lot in identifying them.

Re showing the connections each switch makes in each position is hard to do. My 85 Mercedes 300D wiring diagrams try to do so, by showing a kind of internal schematic of each component, but it isn't always clear what they mean. In most cases, you need to put a multimeter on the terminals and make your own "truth table" for the switch positions. I usually don't and was fooled by the ignition key switch in my 65 Dart (assumed IGN got power in "start" position).

 

[archlab]

I dig what U say about the 'truth table'. That's a great term for what I would also call a 'Baseline', or a 'Benchmark'. I guess that's really what I'm seeking (along w/ Good CAR-ma & Spirtual Fulfilment...I fear I'm a long way from both - Dang!)

 

[archlab]

Arch what year IS your car, to start with

Yeah, I guess I should know to do that first: 1968 Dart, 273 auto. Mopar Performance ECU/Distributor Conversion in 2005-6 (I think).

Anyway, I really appreciate all the time you took to write that reply. That's a nice, real clear run-down. Something about that Yellow wire (& other IGN wires through the infamous middle Bulkhead Connector is hittin' home).

 

[67Dart273]

Measuring the resistance of wires would be extremely difficult .

Exactly why I'm forever tryin' to get guys to learn to use "voltage drop" which is testing wiring under load. Especially since modern digital meters use such little current, you can run a wire from the battery all the way to the trunk, or if the battery's in the trunk, all the way to the front, with say, a no 14 wire to extend one meter lead.

Then you can see what you "lost" at the other end. Only time you cannot do this, really, is when you have a bad short and cannot fully power the circuit.

But ohmeters are FAR more accurate nowadays than they used to be. My Flukes have a low resistance scale with a button push to allow for zeroing out the lead resistance.

You oughta try doin' this with the junk I had as a kid. 1000 ohms per volt, and "pin jacks" for meter switching. Those old meters did not measure much in the way of amperage (maybe 1 or 2) and NO AC current measurements, either.

THIS thing would'ha been a step up