Anyone Know How to Read This Wiring Diagram?

[cpcooper]

So I've been poring over this excellent wiring diagram provided by our host that the Mighty Pieholio (His Pieholiness?) directed me to, and it's all there, everything, but I can't seem to figure out how it's organized. There are TWO index pages that are organized A to Z by letters representing different components, but how did they assign the letters? It took me five minutes to find the headlights, because they are L for sealed beam. Also, the layout has me baffled; fuses are S's and are not in a neat row, but are all over the diagram. I can find stuff after a fashion, but feel like I'd do better if I knew the system and the nuances, like the little numbers on the wires. Go ahead and be as snarky as you want, even if I'm the only one in the class who doesn't get it... I WANT TO KNOW

Pelican Parts - Porsche 911 Parts Listings & Diagrams

[Flat6pac]

That's a walk in the park compared to Turbo manuals that includes Carrera where everything is a black line.
Bruce

[donporfi]

Hope this helps,

http://www.e38.org/understanding%20euro%20wiring%20diagrams.pdf

[boyt911sc]

Originally Posted by cpcooper

So I've been poring over this excellent wiring diagram provided by our host that the Mighty Pieholio (His Pieholiness?) directed me to, and it's all there, everything, but I can't seem to figure out how it's organized. There are TWO index pages that are organized A to Z by letters representing different components, but how did they assign the letters? It took me five minutes to find the headlights, because they are L for sealed beam. Also, the layout has me baffled; fuses are S's and are not in a neat row, but are all over the diagram. I can find stuff after a fashion, but feel like I'd do better if I knew the system and the nuances, like the little numbers on the wires. Go ahead and be as snarky as you want, even if I'm the only one in the class who doesn't get it... I WANT TO KNOW

Pelican Parts - Porsche 911 Parts Listings & Diagrams

Cpcooper,

Don't feel bad if you are having problem reading the schematic wiring diagram/s. It will only take a few hours and practice to understand and follow it. Maybe more than a day. Forget how the alphabets are used for different components parts. It is simply an assignment to designate a given part. For example A= Battery, so the battery in the diagram is represented as "A".

This is how to locate and find the circuit you want. For example, fuel pump relay. Look for the FP relay designation (code).......I am using the factory wiring diagram (US) for '78 SC....... and it is J16. So where the hell could you find J16? Look at the right side column (highligthed yellow), it is located in circuit 108 & 109. So the next question is where are circuit numbers located? At the bottom of the page, you will see another highlighted row from 1 to 100+. These are the circuit numbers.


The trick is to familiarize your self to the nomenclature or alphabet designation of the different parts. Common sense would dictate you to use "A" for alternator or generator instead of "C". After spending many hours even days, I doubt if you could memorize the factory wiring diagrams. Unless you have a photographic memory.

If you have any question, please feel free to ask. We all started like you. Lost and bewildered. One more thing, the number in the square box is the locator where the other end of the wire goes to. For example, [107] @ circuit #57 goes to [57] @ circuit #107. And vice versa. BTW, what particular model and year wiring diagram are you using?

Tony

[T77911S]

porsche wiring itself can be quite confusing. seems to go in loops at times.

just glanced over the link above. good info but not the bible.

jsut one thing i noticed. connectors. T (number) usually refers to how many pins are in the connector. the leter that goes with it tells you where it is using the index.

the numbers are wire sizes in MM. you might see .5mm up to 4mm. about the biggest i have seen.

you have one big sheet but if you were looking at pages, the wires go from left to right for current flow then down thru the load to ground at the bottom.
putting the fuses where they do actually cleans up the diagram. imagine if a wire had to go from the middle of the page all the way back to the far left then back to the middle down to the load it powered. dont let the letters for say an alternator or speedo get you side tracked. just take it for what it is.

reading schmetaics is mostly about getting over all the overwhelming wires on the page and using a system.
i usually start with what i am working on and work backwords. like the fuel pump., start at the power into the FP and work back. usually to relay. work back to the power source (pin30) coming in.
then find out where the power coming into the coil of the relay comes from. if it is another relay or switch work back to the power source of that.
then find out what activates the relay. usually its a ground that is switched on.

take the 930 FP wiring for example.
ther are 2 FP's and essentially 4 relays and a boost switch.
i look it as 2 circuits.
circuit 1 is 2 relays that provides power for the FP's.
circuit 2 is 2 relays and the boost switch.
all circuit 2 is doing is providing the ground to energize the 2 FP relays.

they have done different things over the years. like the 930 drawing. it has "boxes" that show what wires are in the same bundle.

[cpcooper]

Lost and bewildered??? OK, I guess I did open the door with the "be as snarky" thing. I'm working on the 78 US SC diagram. My car is RoW, but still has a B and a bunch of S's.

That link for the Understanding European DIN Wiring is just what I needed, talks about the system the standards, designations, color codes, etc. for wiring I've been working with for years, but never knew, for example, 50 is always battery positive with key on in the crank position, 31 is always ground to the frame. Presumably the same for Porsche, BMW, Peugeot, Fiat, etc. I'll look at some of my British stuff and see if the Brits went along. Anyway, the article pretty much answers my questions and I'm pretty sure after I reread it a few times I'll be a bit less of a dummkopf, even if still somewhat bewildered.

[donporfi]

But beware British cars have Lucas electric parts. LOL

[cpcooper]

[Bob Kontak]

Originally Posted by cpcooper

the Mighty Pieholio (His Pieholiness?)

It is simply a title that has been bestowed upon me.

In truth, someone was talking about "bungholio" (Bevis and Butthead) and I think I threw in a "You need to shut your pie hole" post.

The birth of a legend.

[cpcooper]

You or fortunate, Your Eminence. My own titles are more suggestive of where the pie EXITS the body.

Thanks for your help on the fuel pump relay!

[manbridge 74]

Ah yes, the old world way of wiring schematics. Once you stare at it for a few days it begins to make some sense.

I once spent three full days re-wiring a 77 that had been re-configured by a previous owner. I used two different diagrams and still had a few factory wires that left me puzzled. Probably a difference between markets or mid-year changes. Or AC/non-AC. Or targa vs coupe. Or it was wired up by the sub when the usual guy was out sick.

You might have better luck with a Bentley manual as they show a more typical flow chart diagram.

[Charles Freeborn]

There are 2 kinds of diagrams - A wiring diagram that maps out which wire goes where and to what, and then a current flow diagram, which is more conceptual in nature. When you wrap your brain around the current flow type the concepts, rather than the connections become clear to you. With a current flow diagram, just remember that DC flows from positive (battery) to ground. Then when you understand what the circuit is trying to do (for example power a bulb or motor) the wiring diagram makes much more sense. This sounds vague and evasive, but it's kind of like learning how to play a musical instrument - first you have to learn scales, then you can understand melody.
I STILL can't wrap my brain around the turn signal / hazard light / E-Brake indicator that all share a single flasher unit....
What are you trying to solve? Maybe I can help translate from greek....
PS, once you grasp the concepts, Bosch wiring is dead logical and quite durable.

[timmy2]

Current flow is logical, wiring diagram (point to point) is practical.
The Porsche color diagrams are a lot better than the b/w ones to follow.

Here are a bunch of them with a lot of the missing supplementals that aren't on the main one like power windows, fog lamps etc.
https://www.dropbox.com/sh/03bgz8h8ot93m9c/AACPJ3BqUcIPNCrdpgPYNA0ea?dl=0

[Kraftwerk]

buy some colored pencils already...

[timmy2]

Lol,
As an electrician for over 30 years, looking at prints in B&W daily, the colored ones are like candy...

Coloring them is too much like work...

[javadog]

The terminal designations are industry standard. Buy a Bosch Automotive Electrical Handbook and you can look them up.

Porsche diagrams came is a couple basic styles. They included a sheet that told you how things were laid out, what the labels meant, etc. Might want to track one of those down.

The diagram covers the basic harnesses. There will be other diagrams for optional equipment, usually produced when the option was introduced. So, a diagram for 1978 might need to be supplemented with something else that was released years before.

JR

[T77911S]

Originally Posted by Kraftwerk

buy some colored pencils already...

i was going to suggest colored markers (i just prefer them over the pencils) but if he has a very nice print and has never traced a diagram he could end up messing it up.
its not a bad idea to trace power, i usually use red, to parts that are worked on a lot.
another good one is the turn signals. i hate them. trace red from the power source, then when it breaks off to L and R use different colors for each. this is a REAL life saver because they go everywhere.

i have been an electronics tech for over 20yrs now. all my school schematics are "colored". i even did my 930 diagrams for things i may look at a lot, then i laminated them.
nowadyas you dont need colored markers. everything is jsut block diagrams. ( routers, switches, servers...) kinda sucks.

[cpcooper]

Thanks for all the help and suggestions guys. Now that I'm learning a little about the DIN system, it's getting easier. Still takes me a while to find stuff in the index or legend, or whatever it is, but once I have the current track it falls into place. Also, I figured out I can enlarge the part I'm working up to 500%on with Chrome "Customize" and then display it on my big TV, so no need to go to the expense of a giant print.

[l_turn9]

Thanks for those notes guys -- I've been lurking and absorbing the great comments. Like Charles F, I am struggling with turn signals. I replaced my Turn Signal Switch with a used one that ended up being bad. I then got a new SWF switch and thought things were working but it was temporary. Now, I do not have any headlights or turnsignals, B-U lights or horn. The B-U lights may be a separate issue but I doubt it. I came here to understand the meaning of Track as used on the Wiring Diagrams. I now know they are intended to mean circuits, which I understand. I am trying to understand if the Hazard Warning Switch or the TS Switch could be the fault or maybe I have the wiring messed up. Anyway, thanks for the help! I'll still be lurking so don't hesitate to help an electrically challenged 911 owner ;-)