Assistance with Restoring 73 Wiring Harness |
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Assistance with Restoring 73 Wiring Harness |
doug_b_928 |
Jan 31 2018, 03:55 PM
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#1
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Senior Member Group: Members Posts: 692 Joined: 17-January 13 From: Winnipeg Member No.: 15,382 Region Association: Canada |
My main Winter project is to 'restore' the wiring harness on my 73. I admit that of all the jobs involved in restoring this car, this is the one that creates the most anxiety in me. I took it out of it's container last winter, spread it out on the floor, and promptly proceeded to put it back in the container. But, the time has come to conquer this thing. I have 4 rolls of wire tape that cost more to ship to me than the tape itself, and I think everything I need to do the job. I have pieces of a 74 harness (which I'm aware is not the same) and have already used one of the correct connectors from it for one of the license plate light connectors. Overall, I think the harness could be a lot worse, but there are some areas where POs have made some modifications/fixes and I'm not sure what they've done and why. I'll be asking for assistance from the wiring gurus in the thread as I work my way through. I have the wiring diagram from Jeff Bowlsby's website, a multimeter, PowerProbe3, and cleaning supplies. I'm removing all the tape, inspecting, cleaning, and then installing new tape. I'm just going to clean and inspect the rubber covered sheaths as they seem to be tight around the wires and it seems unlikely that there is anything wrong underneath them (on the upside, everything that ever worked on the car during my ownership, which wasn't everything that was supposed to, still did right before I removed the harness).
Okay, so with that introduction, my first questions. Starting at the back, I've worked my way through the license plate wires, to the trunk light wires, and I'm currently looking at the fuel pump wires. My car had vapor lock, so the fuel pump was relocated to the front of the car. The mechanic just cut the wires, left the ground wire dangling, and spliced in a positive wire which he ran through the firewall (poking a hole; no grommet), under the carpet and through a hole in the front firewall, where he then spliced in the connector and grounded to a screw he added to the front firewall. Here's a pic of the wires: Because of the vapor lock issue, I'm thinking I should put my new pump in the front where the old one was (by the steering rack). I'm thinking of getting the NAPA Bosch fuel pump (N69133). From what I can tell looking at the wiring diagram, and I could be reading it wrong, the power wire goes to the 'regulator/relay plate). If it's source was at the fuse box under the dash I'd splice into the wire up there and put the original connector back on the wires in the engine bay (in case I ever wanted to put an original style in its original spot. If I'm correct about the wiring diagram, then, with my limited knowledge, I guess I have to run the power wire on the outside of the sheath (but at least it will be inside the new 914 rubber snorkel) and up to the fuel pump in the front? Is there any point in running the ground wire that way too, or would you just ground it to a screw on the car as it was before? Also, in the pic above there is a green wire that looks like it had a connector on it at one time. Does anyone know what that was for? When I look at the 73 diagram it only shows the black with red dots and the ground for the fuel pump. On the diagram it shows the, IIRC, 'fan blower motor' having a green wire. However, if that's referring to the blower motor for the heater, I think the wires and connector below were for that (note no green wire). So, to summarize, what's the best approach for the fuel pump wiring, and what is that green wire for? |
bbrock |
Jan 31 2018, 05:55 PM
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#2
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914 Guru Group: Members Posts: 5,269 Joined: 17-February 17 From: Montana Member No.: 20,845 Region Association: Rocky Mountains |
cannot tell much from the pics but if it is a green wire with a black stripe and it is near the original fuel pump lead wires, it is for the optional oil temperature sensor. Original had a plastic housing around it and connected to another wire that was sheathed and led down to the bottom of the sump (IMG:style_emoticons/default/agree.gif) I'm just a couple months ahead of you on restoring my '73 harness but mine needed a lot more work. I just need some sleeving and grommets before I can button it up with new terminals where needed. For the fuel pump, mine had already been relocated to the steering rack area but it was a piss poor job and I'm going to move it up into the fuel tank compartment and add a late access cover. To do this, I bought a few meters of black/red 1.0mm txl wire off ebay (18 gauge is about the same gauge and gxl wire is a closer match to OEM) and ran it from the 14-pin connector through the sleeving up to the front trunk where the pump will go. I have a lot of sleeving missing, so it was easier than yours will be, but it can be done. Find a small stiff wire, make sure the end is blunt so it doesn't tear up any insulation, lube it with some glycerine or electricians lube, and fish it up through the sleeve. Then pull you new wire down through the sleeving. For the ground, I ran a brown wire salvaged from another harness from the new pump location up to the blower assembly under the cowl. When everything is buttoned up, I will add one of these: https://www.digikey.com/product-detail/en/t...627CT-ND/456719. You can't see it in that stupid picture, but it is a dual gender terminal with a male spade coming off the back. The plan is to plug this into the ground terminal at the blower, and plug the blower ground wire into the male spade. You could run your ground to anywhere you like, but this made for a pretty short wire run without having to splice into the harness. This way, the factory schematic will still be correct for my pump even though it is at the other end of the car. If you need other spade terminals, you can get the OEM AMP terminals dirt cheap from digikey. I made the mistake of buying a bunch of no-name terminals on ebay before buying the good stuff from digikey. |
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