I'm scratching my head about this piece on the firewall -- it's a separately mounted component where the battery positive cable connects from the battery positive terminal. A few sub-systems, you might say, are connected there as well, power for accessories, all bolted on the same terminal as the battery cable positive. To the passenger side is another separate terminal, smaller -- what's up with that? I checked it with a voltmeter and it shows no voltage there, no continuity to the big positive terminal. ?? This is a restoration done in the 60's and it's obvious from the paint that this component was/is either stock or of that vintage. The wire connected to the smaller terminal goes to back to the dash, connected to what looks like a (fused, and fuse is good) 6V converter or relay that feeds the stock gauges, among other circuits ... the connection there is at a separate terminal that looks like it's labeled 'batt', although it's hard to see being on your back with your head jammed up among the rest of the jungle there. So is the firewall component bad, being supposed to supply battery voltage to a discrete circuit, if it were working?

 

Welcome to the forum. Is there any way you can get some pictures that show us what you're talking about? It sounds like you are dealing with someone's wiring that we know nothing about.

 

Thanks, pictures ... will do them today. I thought this might be a dumb question calling for an easy answer. Forgot to mention that it's a 12V conversion: battery and generator, and several accessories are all 12V.

 

Sounds like the stock starter solenoid. The ignition switch (or starter button) energizes it to send power to the starter. It's a convenient point to pull power for all sorts of stuff.

 

Hey Oneye,
Welcome aboard! There are several ways to post pics on here. The easiest is to join the site - I think it's $20/yr if you plan to be on here a bit going forward. It also get's rid of the annoying pop-up advertising. You get a paperclip icon that you just click & you can post pics directly from your hard drive - very easy.


Good luck over there in Virginia - look forward to seeing your pics.


Ben in Austin
1950 F1

 

Does it look like this?






That's the starter relay. It sounds like what you've described, and the side going to the starter (large post) will have no voltage present until you hit the starter button (to the small post). But the other side (large post) should be connected to your battery. Lots of other circuits may be getting battery voltage from the large post connected to the battery. Since it's 12 volts, that would be the positive battery post.

 

It's the red unit. I took it off the firewall to take a peek behind -- it's a sealed unit, the back is smooth and slightly indented. The wire connection goes to a relay or converter mounted in the dash. I'll work up some pictures of that to show its connections also, I tracked them down today, maybe that will give more of a clue. Here's the photo URL, hope it works.

 

No the link didn't work...

But here it is. I've never seen anything like that, but someone who's done a 12 volt conversion may chime in here. It's kinda small in the pic, but looks a little like a relay.

 

I'll go out on a limb and guess that's a voltage dropping resistor/regulator for the heater fan.

Is that a Buick nailhead?

PS -- that's a terrible ground connection, it should go to the block.

 

ALBUQ F1, you may be right. The unit in the dash (which the mystery wire connects to), does have a terminal which connects to the heater, which does work. I'll try reading that terminal for voltage with the heater running - otherwise it shows nothing. Have pics of the dash unit, need to figure out how to embed them. All I get when using the add photo icon is a request for a URL. I was using this 'quick-reply' editor, is there an alternative? Yes, it's a nailhead 364. Sweet-running engine, you can just about breathe the exhaust. Only complaint is that everything is so tight -- changing the passenger side plugs involves removing the battery, battery box, frame supports, generator, and everything else in the area.

 

Yeah, I would sort of agree with Ross. I see the large terminal on the firewall as nothing more than that, a place to hook high current 12V. I have a similar multi lug terminal block in a similar location on my '49.
And, like Ross said, get another ground.

 

I'm adding your pics by browsing to the URL of your quick reply editor, right clicking on your photo, selecting Copy image URL and pasting it into the bar at the bottom of the Insert Image function
.








And you appear to have a new original color scheme wiring harness under your dash.

 

Here's the setup in the dash unit. Forgot to mention: think I remember seeing a separate ground, to the block, on the driver's side, while doing the exhaust, will re-check.
So, if everything's working, it looks like the wire to the fuel
gauge should be a 6V supply, via the metal strips, for all the stock gauges. None of them work now. For oil and temp, that may be because of the sensors, or that they're missing, but you would think the gas gauge would
work. I should pull it out of the tank and check.

 

ALBUQ F-1, the block ground is down beneath the oil pressure sender, thick cable to the firewall. I suppose it could be improved by connecting between the two existing firewall ground points with another cable. On another tack, while waiting for the electrical parts to finish up the dash, I've been going through all the trans. swap posts I can find. Mine's a 59T, would like to go to a T-5, and it looks like you've done this, you and BRAIN 75, if I can remember the handle. Apparently this can be done without savaging the crossmember too much? I'm thinking there's probably an adapter for the Nailhead available somewhere, and if so, putting in a T-5 shouldn't involve anything else but fabricating a mount to the stock crossmember and adjusting the driveshaft for length? I would want the O.D. because my rear is a Dana 60 tagged 47/12. It's been polished and chrome-plated, so I can't find any other numbers (as to the year of the housing). I'll be posting a link to a decent set of pic.s pretty soon. So am I anywhere near on a right track concerning the T-5, to come up with a decent highway rpm? There's what looks to be a nice one on eBay right now: eBay item number: 111513954731

 

Here are some pic.s as promised: