1973.5 Wiring Help

[jac1976]

Putzing around in the trunk when I found a wire that leads to nowhere. At the fuse box, there is a red wire with a green stripe that is not connected to the block. So far, I can follow it back to the bulkhead, but I lose it after that. Any thoughts? Thanks.

[haycait911]

my chart shows it runs from the fuse block to the 'warning light switch', or four way flasher.

[jac1976]

Haycait911,

Thanks so much for the quick response. I'll look into it.

[E Sully]

The only Red/Green wire I know of is from position 7 on the fuse panel to the fuel pump in the engine compartment.

[haycait911]

funny. three 73.5 owners all in one place.

Ed, I'm going off the 73 wiring diagram. maybe a '74 onward wiring diagram would be more appropriate. would the pump wire run into the bulkhead though? not into the main harness loom running to the rear of the car?


jac1976, maybe check what color is at your fuel pump. someone may have wired it to another source. I'll be at my car tomorrow and I can see what it has at the pump, it's pretty original car.

[haycait911]

duh! I just found this. pelican has the 73.5 specific wiring diagrams.

Pelican Parts - Porsche 911 Parts Listings & Diagrams

and have I mentioned how much I hate 'current flow' diagrams.

[jac1976]

Been beating myself over the head with the Haynes manual. As Ed suggested there seems to be a red/green from position 7 and is illustrated as such in the Haynes for 1973. However, the 1973 CIS diagrams seem to muddy the waters for me as the key seems incomplete. Perhaps it should be used as an addendum to the early 1973 diagrams?

Not with the car at this writing, but I agree that looking at the fuel pump may clarify.

For further disclosure, I have replaced the original fuel tank, sender and other components after the car sat for a protracted period of time. This may further confuse the situation. In addition, I may have misdiagnosed a problem last week with the motor not turning over as a weakened battery when it may have been a fuel pump issue.

Nevertheless, I really appreciate the input as I find the advice in this forum far exceeds any shop manual.

[jac1976]

So on the Pelican diagram, what is represented by the "8" at the end of the red/green wire coming from position 7?

[ossiblue]

Originally Posted by jac1976

Been beating myself over the head with the Haynes manual. As Ed suggested there seems to be a red/green from position 7 and is illustrated as such in the Haynes for 1973. However, the 1973 CIS diagrams seem to muddy the waters for me as the key seems incomplete. Perhaps it should be used as an addendum to the early 1973 diagrams?

Not with the car at this writing, but I agree that looking at the fuel pump may clarify.

For further disclosure, I have replaced the original fuel tank, sender and other components after the car sat for a protracted period of time. This may further confuse the situation. In addition, I may have misdiagnosed a problem last week with the motor not turning over as a weakened battery when it may have been a fuel pump issue.

Nevertheless, I really appreciate the input as I find the advice in this forum far exceeds any shop manual.

E Sully is correct in that the red/green stripe wire should go back to the engine compartment and is for the fuel pump.

Be aware! If your fuel pump is in the factory position, above the left, rear wheel, and you look at the wire colors at the fuel pump itself, they will be different than the red/green stripe. The red/green stripe wire terminates at a connector inside the engine compartment, near the CDI box and fuel accumulator. From that connector, two different wires, one blue and one black, run down through the frame to the pump location and make the actual connection.

Now, that's on a factory set up. Since your red/green stripe wire is not connected to any power, it must have been replaced. I suggest you start at the pump itself, and trace the wires from there, to the connector in the engine compartment and report back what you find, including the colors of all wires you see and to where they are connected.

[ossiblue]

Originally Posted by jac1976

So on the Pelican diagram, what is represented by the "8" at the end of the red/green wire coming from position 7?

Fuel pump, after the connection to the blue and black wires. (Look at Part II of the diagrams.)

[E Sully]

jac1976, there are 2 parts to the 1973 diagram. The 8 on part 1 is continued on part 2, which goes to the fuel pump 8. The key for the diagram is incomplete, but the Legend(key) for the earlier 1971 diagram has most of the missing info. They are very similar.
Yes, the Rd/Gr and Brn wires change to Bk/Bl at a connector 87 by the engine bay console.
A few pictures of what you have would help. Here is a picture of my front fuse panel. You can see the Rd/Grn on the right side in position 7. Just to be clear, this side of the panel is the feed side from the battery, and the wires on this side are not protected by the fuse.
Actual wiring is mirror image of diagram.

[jac1976]

Ed, thanks so much for snapping those photos.

Here is what I found above the rear left wheel. The red/green wire, along with a brown wire terminated in a connector that connected nowhere.

Obviously these are no longer part of the equation.






Thanks again for everyone's continued feedback. I am sending with a few additional questions.

[jac1976]

Thanks again for everyone's continued feedback. I am sending a PM with a few additional questions.

[jac1976]

[E Sully]

jac1976,
The picture of the R/Grn and Brown wire connector is the original feed for the fuel pump. There is a second small harness that would then connect from there to the fuel pump using
Blue and Black as shown in the diagram. If you could get pictures of how yours is actually wired then might be able to figure out what has been changed. Also, I see a brown wire that is loose, that should most likely connect to a tab on the CDI box.

[Sunroof]

Per Ed...."Be aware! If your fuel pump is in the factory position, above the left, rear wheel, and you look at the wire colors at the fuel pump itself, they will be different than the red/green stripe. The red/green stripe wire terminates at a connector inside the engine compartment, near the CDI box and fuel accumulator. From that connector, two different wires, one blue and one black, run down through the frame to the pump location and make the actual connection".

This is vertified......I changed my pump out several times over the course of ownership on my 1973.5T and the black/blue wire do connect to the pump.

Bob
73.5T

[pors1968]

Ed is right on fuel pump wiring.This wiring set up is wrong there no protection .The red green wire overheat and melt and cause short .