I get that. But without knowing the spec for both senders I wouldn’t assume they’d run the same gauge. Especially with the King Seeley’s and the feedback mechanism in them. But as FD points out, if you backfeed the harness from the radio wire you should power up the whole “accessories” side. You might also power up the “run” side. So no loose wires to ground under the hood or anywhere else. Now you can check the sender at the wiring in the trunk. Separate ground jumper from sending case to body, and wire from gauge hooked up to sender. You can also briefly ground the wire at the trunk and see if the gauge moves. If it does, and not with the sender, you know the sender is functioning.

Don’t forget the small fuse in the battery feed. Even a little RV battery can short a lot of amps to ground, enough to melt wires or start them on fire.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Miker, I was hooked up to the temp gauge, not fuel gauge. I don't know if the temp gauge will react to the fuel sending units stimuli or if it's different from what causes the temp gauge to react normally. It was way easier to get to the back of the temp gauge.

Brad
Sierra Vista Arizona
1954 Lincoln Capri

____________________________

I like FD’ s idea of back feeding the radio line. Make sure everything that’s loose is isolated and don’t forget the fuse on hook up. I’d start with the positive side grounded, like original. See if the gauge moves. Seems to me in a prior post you said the gas gauge moves from E to F when grounded. So you’re really just testing the sender and its compatibility with the guage. If it works, reverse the leads. I don’t think the King Seeley’s are polarity sensitive. But you’ll know.

It’s also not really important if the gas gauge is that accurate. What’s important is that it reads empty just before it runs dry. I’ve had numerous vehicles that went long miles on full, and then dropped quick. It tells you to go buy fuel. You know when it’s full because you just put the cap back on at the gas station.

Since you didn’t get any ohm readings thru the sender, don’t be surprised if it doesn’t work. But if no one here knows a rebuilder, I know there’s been a couple come up over on the Ford Barn or the HAMB.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

It is  usually very tight behind an instrument panel. Since at this time you are only trying to check the fuel and temp instruments, it may be easier and safer to feed the accessory circuit through the radio feed wire. I don't have a wiring diagram for a 54 Lincoln car but usually the radio feed comes from the accessory termial as does the gauges. If you disconnect the radio feed from the radio and apply your 6 volt negative supply to the radio feed wire and the positive to ground, both gauges should have power so you can then test the two instruments in the usual manner. Also, what ever else is on the accessory circuit will be livened up too.  I would strongly take Miker's advise and install a fues inline with your power source just in case. Good luck and hope this helps. 

64F100 57FAIRLANE500

OK. So I brought a 6 volt rv battery into the interior of my Lincoln. I have a 6 foot long set of cables with clips on the ends. I tried to hook them up to the back of the gauges but couldn't reach it. I was wondering if I could just use another gauge that was accessible? I tried the temp gauge but wasn't sure if I was hooking it up right. I didn't take into consideration that it's still pos ground. I grounded the Batt neg to chassis and one of the cables coming from the gauge to Batt pos. The other cable from gauge to sending unit. The temp gauge went from cold to hot, but very slowly. It didn't move again when I moved the float, so I'm wondering if either that gauge won't respond to what I'm hooking up to it or if I am hooked up wrong or the sending unit is bad. I'm just checking the sending unit now because I cleaned put the tank and want it to function correctly when I put it back in.
I also have a question about if this sending unit will still work when I convert to 12 volts neg ground.

Brad
Sierra Vista Arizona
1954 Lincoln Capri

Yes that would work. But make yourself a jumper up with an inline fuse for the non grounded terminal battery terminal. When I’m doing what your doing (or doing check out on a just rewired car) I start out with about 5 amp fuse, go to a 10 for dash lights, parking etc, and finally a 20 amp for everything else in turn. A lot easier to blow a couple small fuses out in the open than to go looking. Or having a direct short and melting something. Once I know all is ok, I’ll actually hook the battery up and check the starter solenoid and starter.


miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I could put battery in the interior of the car and hook jumpers to the back of the gauge and jumper from other side of gauge to sender , also in the interior, move float and look for gauge movement?

Brad
Sierra Vista Arizona
1954 Lincoln Capri

If the battery was installed  in the vehicle then the system would be live. Since your engine is still out of the vehicle, I would be concerned with all the stray wires dangling about and possibly shorting out or grounding out making sparks and smoke. One of the ways to at least test the gauge for movement was mentioned earlier in this thread. That is, with the ignition in accessori, very briefly touch the wire that was attached to the sender to ground. The gauge, if working, will start to move to the full position. I would guess that the gauge probably works as they are very reliable. If ever there is an issue, it's usually the sender. If indeed you do get the battery in the vehicle, then why not, with sendere in hand, ground it , then attach the wire to it and see if the gauge responds by moving the float arm?  

64F100 57FAIRLANE500

OK, thanks for the info. So if I have a 6 volt battery and hopefully the gauge still works, how would I conduct the test? I can set it up in the car and hope the gauge works to test. No idea how to wire it to test.

Brad
Sierra Vista Arizona
1954 Lincoln Capri