Help identify these two wires! 77 911S 2.7

[thebng]

Happy Thanksgiving! Hopefully, this will be the last of my juvenile attempts sorting the wires on my 77 2.7! Thanks to all for the help so far. Here we go. There are two wires in question that I can't find on my flow chart for the 77. One wire is a yellow wire with a green stripe, the other wire is what looks to be grey with a brown stripe. Both of these wires are heatshrunk together as a pair from the factory with a heavy gauge plastic sheathing. There is also an additional plastic pvc sleeve over these two wires. I am including two pics.


The first is where it goes through the firewall along with the red and yellow wires for the starter. You can see the black plastic covering these two wires behind the yellow and red.


The second pic is of the wires themselves. They are about two feet longer than the starter wires and someone rigged an extension and two bullet clips on the ends. Like i said earlier, the original wire colors look to be yellow with a green stripe and grey with a brown stripe.

Any help is appreciated. When I got this engine, the engine harness was originally set up this way, that being said, I have found out that it wasn't 100% correct. Thanks again.

[gsmith660]

Maybe they are the backup light wires

[ossiblue]

Originally Posted by gsmith660

Maybe they are the backup light wires

Good guess.
Try putting the car in reverse (motor off), turn on the ignition, and see if you get current through one of the leads. I'm not an expert by any means, but I know of no bullet connections in the area save for the reverse light switch on the tranny which uses a plug with round prongs. Could be a PO replacement for the plug.

[fastfredracing]

Sure looks like the back up light swithc wires. they connect up at the front lower portion of the transmission. Just above the front crossmember Happy Thanksgiving!!

[P Moore]

Yeap 100% the second picture is the Reverse/back-up lights,
I see someone made them that bit longer, i done the same as there is not alot of slack...

[thebng]

Thanks for all the replies! I thought the same thing about being the reverse lights, but the thing is, there is current running through them even with the car in neutral. Also, it looks as if these wires are originating from the engine harness, and not the body harness. This being said, if I plug into the trans tail shaft, it will be running from there to what looks like the back of the engine. So please correct me if I am wrong, but if it was the backup wires, shouldn't they be running right to the tail lights via the body harness and not the engine harness? Will scope around the back of the fuel injection tomorrow to see if I can find out where they terminate. Thanks again all!

[gsmith660]

Nope if you look on the wiring diagram they get to the main harness via the 14 pin plug it should have voltage on 1 wire and the other wire should go to backup light the switch is what you plug into and then goes to provide power to the backup lights which are grounded by the rear tail light housing. The wire should only have voltage when the key is on.

[gsmith660]

You should be able to trace it to the 14 pin harness easier than digging around the back of the motor mine disappears in to the engine harness.

[boyt911sc]

Originally Posted by thebng

Thanks for all the replies! I thought the same thing about being the reverse lights, but the thing is, there is current running through them even with the car in neutral. Also, it looks as if these wires are originating from the engine harness, and not the body harness. This being said, if I plug into the trans tail shaft, it will be running from there to what looks like the back of the engine. So please correct me if I am wrong, but if it was the backup wires, shouldn't they be running right to the tail lights via the body harness and not the engine harness? Will scope around the back of the fuel injection tomorrow to see if I can find out where they terminate. Thanks again all!

thebng,

These guys got it all correct!!!!! These two wires (yell/grn and brn/grey) came loose/off from the back-up light switch located at the front end of the transmission. Just plug them back in and you'll get your reverse light. The yellow/green wire came from 14-pin connector @ #5, while the brown/grey wire @#6. Insulate the yell/grn wire and prevent it from touching any metal parts of the car because it is energized when the ignition switch is turned ON.

Now, even with all these explanations and you still curious to know where these wire terminate, just pry open the 14-pin connector. Inspect terminals #5 and #6. The other end of the brown/grey wire at the 14-pin connector goes to the back-up lights. Refer to the factory wiring diagram for better understanding and visualization.

Tony

[thebng]

Thanks for clearing up all my confusion! Gsmith660 you have been a great help. If you were closer, beer would have been on me! And Tony, thanks again for your wiring input. You guys are always right! Thanks.
Matt