My Factory Wiring Diagram Doesn't Match My Car!

[Scott Clarke]

Why is this? My car is an E made in 10/69, so is quite early. It does have two front fuse boxes, one with 10 and the other with 8 fusees (Per m.y. '70), but many of the wires seem to not be the colors indicated in either the m.y.'69 or m.y.'70 diagram. Is this normal? The wiring has no indication of being unoriginal.

[911pcars]

How do the color codes in these wiring diagrams match with your vehicle?

http://members.rennlist.org/911pcars/WiringDiag.htm

These are scanned from the factory manual.

Sherwood

[Scott Clarke]

Sherwood-
I'm not getting those to open for some reason, but I suspect that they are the ones I'm refering to, SL-33 and SL35. Mine are from the first two volumes of the factory workshop manual.

[edmayo]

The 69 wiring was a one year only system and although basic wiring colors have been essentially the same since the 356's (can't say that about all cars) there are some physical location differences. You need first to determine if your car was built with 69 or 70 model wiring. The most obvious difference was in the engine compartment, for 69 ONLY the harness from the car tied to the engine via 4 round, black, 6 pin bulkhead plugs that were attached to a metal frame on the shock absorber cross member. ( these would be where you would disconnect to pull engine) The 70 and up harnesses disconnected over by the relay board (left side of engine compartment) via a 14 pin connector. Let me know which you have as I have the specific 69 wiring diagram. For the most part 70 thru 73 were the same.

[911pcars]

Scott,
I downloaded one of the PDF files and it opened okay. PM me your email address and I'll send them to you so you can match with your car.

Sherwood

[Scott Clarke]

Sherwood-
Thanks for the offer. I, too, was able to download the files. I'll print and verify that they match those from my manual.

Ed-
Thanks for the clarification on the '69 harness. Based on your descripton, mine is definitely '70.

Is it people's experience that the factory diagrams accurately relate to their cars? Are colors generally consistent?

[911quest]

I was in a German car repair class once (Audi) and we were complaining about the color's of the wires not being correct and they told use if we keep complaining about it they will make them all white. Have you ever seen the engine wiring on a 914 all white.

[edmayo]

I really can't remember if I've ever found a mistake in the Porsche diagrams, and same goes for the color codes. Listening to friends describe Ferrari wiring gives me cold chills, there's a reason I don't work on those. We are spoiled!

Yes the 914 F.I. harness is all white wiring, but each wire is number imprinted about every foot or so, same as aircraft wiring practice. Not enough color combinations for all the wiring in a plane.

[Scott Clarke]

Upon further inspection, it seems that previous caretakers of my car have been less than diligent in maintaining the correct position of wires into and out of the fuse boxes. In addition, the left and right sides of the fuse box are reversed relative to the way they are read on the diagram. This resulted in a very slight resemblance between the car and the diagram. I have that much sorted out, now, and have reviewed the wiring to all of the gauges, which was removed in the course of the current, 5 year, project. There seem to still be many instances when the colors on the diagram are not literally the same as those on the wires. I think that the diagram is about 85% accurate, unless there has been more shuffling over the years, but I think it is more likely that there are discrepancies.

It is the case that I was not nearly diligent enough in documenting the positions of the wires when the car was disassembled. I'm now a believer that you cannot over-document stuff. Use pen on labels, not pencil. Label everything, even what is seemingly obvious. Take a lot of photos and notes! Live and learn.

[304065]

Scott,

You have the right diagram now, good.

The wire colors, like pretty much everything else, conform (mostly) to a DIN standard, number 72552. Google up DIN 72552 or look in the Bosch Automotive Handbook for some interesting information.