Today's question: I think I've figured out how I will run the 12G wire through to the steering rack area. I'm going to run a ground from the ground point screw by the frunk release handle to the fuel pump at the steering rack. I have a piece of salvaged ground wire with a ring connector but it appears to be 16G. Given that it's a far shorter run than the 12G + wire, am I ok to ground the fuel pump with the 16G wire? If not I can get a new ring connector and make a piece out of 12G.

I have the exact same question.

Fellas, its a circuit. From the power wire, through the pump, to the ground. Its only as good as its weakest link. So a 16 ga ground wire in a 12 ga circuit would be the weak link and may not protect your pump or the + wire.

The stock 75-76 FP ground cable is a stout cable that goes to a screw to the chassis under the fuel tank.

Makes sense, thanks Jeff!
PS. Does the mystery harness look at all familiar and anything I need to do to prevent the melted wire issue from the headlight switch?

Don't know about the mystery harness. It may be a piece of some other harness, I am not familiar with it. Cannot say about the melted wires - that could have been caused by many things. Two loose power contacts rubbing together, abraided wires in contact, a shorted switch or other component. Just be thorough in your inspection.

Perfect, thanks Jeff!

My extremely limited knowledge of electronics continues...I'm trying to figure out the relays. A PO had disconnected two wires (going to fuses 2--white and 4--yellow) from the combination relay. I'm putting everything back to stock per the wiring diagram. Here's the diagram for the combination relay:

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So the wires should connect to the relay as follows:

White = F
Red/white = 56
Yellow = 56a
Yellow/red = S

Here is the schematic on the side of the relay:

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And here are the connectors on the relay:

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The only code I can see that corresponds to the schematic is 56a, which is the spade in the middle.

So, the question is, how do I know which of the other terminals is which?

Hoping someone will chime in about my previous post in terms of how to read the relay schematic so I know which pins are which. In the meantime, the power antenna and radio were wired by soldering in wires with in-line fuses as shown below:

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The Radio is wired to Fuse 8 which includes the cigarette lighter.

The antenna is wired to Fuse 11 which includes the interior light.

Is this an appropriate way to power these devices? I'm guessing that Fuse 8 (cigarette lighter) gets power when the key is turned on. But I wonder if Fuse 11 has constant power because it includes the interior light? If so, should I power the antenna from fuse 8 as well or does the radio itself tell the antenna to raise and lower?

Basically, I guess the main question is what's the best way to wire the radio and antenna into the original fuse panel?

I just searched some old pictures and it appears the modified wiring originally looked more like this?

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So, it looks like fuse 12 (on the direct connection to battery side) was wired to an inline fuse that then went to the fuse 8. Not sure why they did this.

The antenna was powered from fuse 11

And probably the radio was powered from fuse 10...

So, to instead of figuring out what the PO had done, again, the best way to ask is, what is the correct/best way to wire in power for the antenna and radio?

If you don't want to buy 12ga wire for this one short run. And if you don't mind appearance in that short distance, you can use three 16ga wires in parallel to the same connectors/lugs. You can heat shrink them together to make the wires look 'neater'. Otherwise just buy some 12ga wire to make it perfect

Here is a wire gauge calculator for length vs amps:

https://www.wirebarn.com/Wire-Calculator-_ep_41.html

Yeah, it's ugly to say the least. For starters, I'd put female spades on the radio and antenna wires and slide them onto the back of the fuse panel the proper way. There are several slots that have extra lugs for plugging in extras both before and after the fuse in the panel. I don't understand the jumper between fuse 12 and 8. Seems like a bad idea.

Somewhere I thought I ran across which fuse the factory radio harnesses plugged into, but for the life of me can't remember where, nor whether a modern radio would draw more power than whatever the factory or dealer would have installed. If nobody comes to the rescue with an answer, I'd be inclined to leave the inline fused in place, and plug them into whichever fuse has the fattest wire coming from the battery and an extra lug BEFORE the fuse. That way the radio and antenna would be protected with the inline fuses without running current through the fuse on the panel and possibly overloading it. I've never had an automatic antenna, but can't imagine they draw much power and how often are they operating anyway? I'd be inclined to twist the radio and antenna wires together and crimp a single female spade on the pair.

Now let's see if Jeff or anyone jumps in to point out how full of I am.

Thanks very much Brent. Yeah, after all of this I definitely want to have a more professional installation. How do I know which terminals on the fuse panel are switched with the ignition?

Other outstanding issues:

1. I still don't know how to connect the wires to the combination relay (as outlined in my post above).
2. I don't yet know what radio I'll get (probably something that looks somewhat period correct but that will allow blue tooth etc), but do most have a power wire for the antenna or is that a separate power going directly from the fuse panel to the antenna?
3. A PO had installed an electric motor for the WW fluid. I understand that originally it would have had a pump that ran off of the air in the spare tire. I'd like to go back to original (this car will be a fair weather driver so electric pump is not necessary).
4. Where was the original button to activate the WW fluid?
5. Also, is the pump pictured below the original pump?

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Did a little searching and see that there was not washer pump at all originally. I'm guessing what's pictured above was someone's solution to the spare tire pump?

If my memory is right the radio clips to Fuse #7 but need to confirm.

That pump looks like it might be the pump for the factory headlight squirter system. If so its golden. Do you have any other parts to that system such as the squirters on the front rubber bumper pad?

Thanks very much as always Jeff. I'll await your confirmation for which fuse to go to for the radio and antenna. Is there a gauge that is best for radios?
I'm thinking now's the time to run wires for an electric washer in case I decide to go that route. The POs method was not pretty. Do you have a recommendation as to what to do to be 'electric WW motor ready' (e.g., where to run the wires, how many, what gauge, etc.)?
I don't recall any other parts as shown in the diagram you attached. Certainly no outlets on the front bumper top, but I suppose that could have been changed though I don't know why since the car is unbent on the front.

I know I have seen a harness with the radio at fuse 7, but also found this from the Dr.:

"the factory source was the cigar lighter Many though have tapped the second or third fuse over from the passenger right side so that
they could operate the radio without having to turn the key on"

Thanks again Jeff!

As an update, here's a before and after of the fuse panel. It occurred to me that the labels might be an issue. I checked them for continuity and nothing. I assume that means they won't conduct electricity. But are they a fire hazard somehow?

Any chance you can make sense of the connectors on the combination relay above?

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Looks good. Hope you see now why I don't recondition these chassis harnesses.

Thanks Jeff. So to make sure, no fire issues with the labels? I chuckled with your comment because several times I have thought to myself “now I know why Jeff doesn’t do full harnesses anymore!”

I would not label them permanently, but I see no harm.

Excellent, thanks Jeff. I'm leaving them for next time I have to go back in there (Don't want to have to through all that again if I can help it).

I'm with you here. People like to "upgrade" to electric pumps, but I think the original system is pure genius and one of my favorite quirks on a car that has so many of them. As you discovered, there is no pump. Just a hose from the spare tire to the fluid bottle, another from the fluid bottle to the switch, and then from the switch to the nozzles. On a '73, the washer is activated by pulling back on the wiper lever. A couple things if you restore it. First, get the right hose. It is under pressure and regular washer tubing will burst and leave you with a wet lap. 914rubber had a bunch of hose kits, not sure if they still do. Second, the connector that screws to the tire has a valve in it to make sure you maintain enough pressure in the tire to use it as a spare. You fill the spare to the max pressure on the sidewall and when you get down to something like 25 lbs. it shuts off.

Other than learning about the hose thing the wet way, I always thought the system worked beautifully even when teeners were out only cars for year round driving.

Nice work on the fuse panel. I'm doing the same with the labels. I'm leaving them on until it is ready to go back in the car.

Thanks for WW fluid system explanation, Brent. Do you know if anyone sells a kit with everything to restore it?

I’m thinking I should still run a couple of wires (I’m guessing a positive and ground) for an electric pump just in case. Any thoughts as the appropriate gauge I should add?

My plan is to leave the labels on the whole harness. It will make it easy for the next person in another 50 years. I’m also not leaving gaps between the tape. I think it looks nice that way but after all the work cleaning the wires (which were dirty where they were exposed) I’ll sleep better knowing they will stay clean; and again the next guy will appreciate that someday too

Update: I’ve added a couple pieces of wire (look like 16G) for power and ground to the WW pump so I have the option to go electric. I also see the black and brown wire for the intermittent wiper relay. From Sir Andy’s write-up in the tech section it looks to me though like the best way to power the washer is just use the brown/black wire for the intermittent wiper relay. Do I understand correctly that he relay is not needed, rather that wire gets power when the lever on the steering column is pulled (from the write-up it looks like he splices into that wire before the relay location)? Either way I’ll leave the added power wire as a backup.

Technical question: the small black with blue wire that gives power to the gauge cluster lights was spanning from the gauges to the fresh air controls from outside the taped harness. It is originally that way, at least for this harness. It would be so much neater to make it a little longer (about 18” at most) and have it follow the loom for the fresh air instead of being a wire on its own getting tangled spanning two branches of the main harness. I measured he resistance in its original configuration as 14 ohms. Then I cut it and spliced in a piece and then rechecked the resistance, finding it to be 24 ohms. I realize that the longer the wire the greater the resistance. But that got me wondering if the factory had it that way to avoid problems with it being a bit longer. Will that change in length of a small wire create any problems?

Winter job done (with the exceptions of needing to solder back on the original fuel pump connector once I bring it out of storage, new snorkel, and adding terminals for the new fuel pump and WW wires once I have them trimmed to the correct length). I just wanted to say thanks to all who have replied to my questions in this thread. Your assistance gave me the confidence to get through what I felt would be the most intimidating job of this entire restoration. Also, if anyone who reads this thread has answers to the unanswered questions above, please reply as I'd still like to know the answers. Here's the pic of the final product...

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Thanks Brent. There are two questions that I forgot to ask that are still bugging me a bit:

1. In the wiring for the Fuel Gauge (shown below), there is a brown with white wire that exits and goes through a diode, and from the diode it branches into two wires going to the safety belt warning light and the parking break contact. I could not get continuity through those wires. I removed the diode and could not get continuity through it. I did a little searching and could not see whether or not there should be continuity thorough a diode. But I assumed not. Should there be? Per what I read I tested the resistance in both directions and found different readings in each direction which indicated the diode is good. I'd like to know for sure if it's good before installing the harness back in the car. Is there anything else I should do?

2. The Turn Signal/Emergency Flasher Unit looks like a relay, but the pins are not marked the same as the other relays and when I looked for continuity across any two pins I could not find it. I have a spare from the parts harness and it behaved the same. Is this unit a relay or something else?

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Update re testing a diode: I found this youtube video which explains it well. My diode tested at .560 in 1 direction and OL in the other, so hopefully that means it's good .

https://www.youtube.com/watch?v=qSDRsz5-t7I...lay=1&rel=0