Rewiring TO30 - What the heck is this in-line thing?

Re-wiring my new TO30 and have no idea what this thing is or why it is there. See photos. It is located in-line between my Ignition (key) switch, and my Delco Remy 12 V Generator. It says "14 V Littel Fuse". It looks primarily like some type of indicator light. It is a sealed unit and can not be disassembled. I got onto Littel fuse web site, and there is nothing in their products section that looks like this. I don't know whether to re-install it, remove it, or just replace it with a modern automotive fuse holder and fuse. It is not a resistor or ballast, however, sometimes people use indicator lamps or diodes for resistance in a 12 V conversion, but that should not be needed between the Alternator and the ignition switch. If anyone has seen this before and knows what it is and why it is there, please please let me know. No other rewiring issues to mention. Tractor has been operating just fine since I bought it, so the temptation is to just re-install it, but I would rather know why it is there. Thanks again to all, Larry.
 
Trying again to post photos.
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A web search for Littelfuse indicator light turns up some 120/125 volt indicator lights that look like that one, except white housing. It is likely an indicator light that is NLA.

You say it is in line between the switch and generator. Was it mounted or just hanging in the wiring?

This post was edited by Jim.ME on 06/27/2022 at 05:40 am.
 
"sometimes people use indicator lamps or diodes for resistance in a 12 V conversion, but that should not be needed between the Alternator and the ignition switch"

That's EXACTLY where you use an indicator lamp, diode, or resistor, to prevent current feedback from the #1 ''excite'' terminal on the Delco alternator to the ignition system, which can prevent the engine from shutting down when the ignition is switched ''off''.

Does the indicator light up when the ignition switch is ''on'' and the engine not running?
 
You first said, "It is located in-line between my Ignition (key) switch, and my Delco Remy 12 V Generator." Later you said, "It is not a resistor or ballast, however, sometimes people use indicator lamps or diodes for resistance in a 12 V conversion, but that should not be needed between the Alternator and the ignition switch."

Which are you asking about? Generator and alternator are not interchangeable when talking about wiring for them. Has it been converted to an alternator? If it is an alternator, is it external or internal regulated? If internal regulated, is it a one or three wire? wore out is right; an indicator lamp (incandescent), resistor, diode, oil pressure switch, etc. is needed if you have a field excitation circuit needing a power supply for a three wire alternator to prevent back feed. Such is not needed with a true one wire alternator.
 
Sorry for my miss statement. It is a 3 wire Delco Remy Alternator, 12 Volt, not a Generator. As the ammeter does not work
on this new acquisition, I have no idea yet as to what the RPMs need to be to excite the Alternator. I had thought that
the only place people install resisters or diodes was in line with the coil. In this case there is an external resister
attached to the round coil (which I will soon replace with a 12V coil with internal resistance). My question firstly is,
what is this thing, and once I know that, if it is an actual fuse or circuit breaker, or if it is something else, then I
would be able to diagnose the characteristics of the Alternator. It is confusing for me because 1) all my other tractor
alternators are single wire, and 2) none of my other tractors have anything like this in-line. Thanks, and sorry for the
confusion, Larry.
 
Have not checked on whether or not it lights up. It was zip tied into a wire loop bundle between the battery and the dash.
I will re-wire it in with the item exposed, and test to be able to answer the question. Heavy rain today, will do so
tomorrow.
 
It was not mounted, see prior post, it was zip tied into a wire loop bundle between the battery and the dash where it was
only visible after I removed battery and started the re-wiring job.
 
woreout, I just re-installed the unit so I could see it with the battery installed. The results were (with the engine not
running), ignition off (no light), ignition on (no light), ignition and lights on (lights up), lights (lights up). Kind of
strange as the tractor has no lights installed so I run it with the key just in the first position (where the unit does not
light up) and have had no problems. Would have been less confused if it was marked littellight rather than littelfuse.
 

Have you traced the wire this light is located in, to both ends? Where do the ends connect? Is your ignition switch a combination ignition and light switch?

I suppose a lighting circuit terminal of a combination ignition/light switch could use a light terminal to excite the alternator and not have a back feed to the ignition terminal from the alternator. You would need to turn the switch to lights to start the alternator charging. If the Littelfuse indicator is LED, it may not carry enough current to properly excite the alternator, generally an incandescent light is required for that function.

You said, "Tractor has been operating just fine since I bought it,". So, was it charging before you started your re-wiring? If you don't know if the alternator is working, it might be worthwhile to have the alternator checked before going any further. If the alternator isn't good, you could easily change it to a one wire like your others now, if you want, and rewire correct for a one wire.
 

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