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light switch housing wires cut at center oammeter

R

Rich ORourke

Member
Hi, when i open up the sheet metal cover where the light switch is on my farmall H, i noticed that there is a wire cut off from the center of the back of the ammeter, but there are still wire going into one terminal, and wire going out from the other terminal, what is the center wire cut off from the back of the center of the ammeter for? Also, there is no fuse on the back of the bakelite board where the light wires screw into. There is only one fuse holder clamp, shouln"t there be two? Can I send a picture to somebody who can help me figure this out? This is a 1942 Farmall H, with a 1948 engine and seat and who knows what else, but the 6 volt system starts like a champ every time with minimal effort and runs at low idle at 4oo RPMS. thank you very much to anyone who can help!!!
 
Rich,Bob M has wiring diagrams of all antique Farmalls plus has a picture of the wiring of a light switch,I have it {I THINK }in my favorites,but I dont know how to post a email address here.I hope some one else reads this and has bobs address,hes on here regular

jimmy
 
A center wire on an ammeter sounds kind of odd -- it's a simple gauge and usually involves just two terminals one to hot, the other to ground and it measures the juice running betwen the two-- so I'm not sure what a third terminal would do. It is the back of the ammeter you're looking at and not the switch, right?

Check out the diagrams at the link below. They might be of help in sorting things out.
BobMs Very Helpful Diagrams
 
Yes, that is correct, there is a black protrusion from the center of the ammeter guage, and there is a insulated wire cut off very close to the knob in the back of the ammeter.
 
If anyone has a real photo of the back of the light switch showing how the fuse circuitry and wires look with the resisters, my email is [email protected].
Also,the field resistor that is supposed to be in the housing.....can that be placed on the voltage regulator also....I ask this because there is a small spiral tower on the voltage regulator that looks like it could be some kind of resistor. thanks, Rich
 
By any chance is your ammeter original or is it possibly some other after market meter? If it is not original, it could have, at one time, had been a lighted meter and someone cut the wire off at the back center of the meter.
 
I don't hae a photo that I can scan and send, but if you've got a four-position switch (which would be the case if you've got a field resistor in addition to the dimmer coil on it) look at Bob's diagrams 3 and 4, depending on whether you have a magneto or a battery ignition. It's as clear as any photograph and, in many ways easier to see what's supposed to go where. The body of the switch should be pretty much square as the diagrams show, with the field resistor hanging off into space at the bottom at a bit of an angle. If the body of the switch you have is round, it would be an aftermarket replacement, though I'm not sure how long those have been available.

As far as that center wire in the ammeter, Farmer Bob's idea about it being aftermarket with a backlight is as good an idea as any I could come up with.
 
That could very well be, since this guy jerry rigged everything, and the back of the light switch circuit board is missing one of the fuse holders and dthere are some screws with no wires on them!
 
There should only be one fuse holder. Is that what's missing, or just the fuse in it? If the switch is rectangular, indicating original, like those in the diagrams, it would be pretty hard to remove the fuse holder, as it was just two clamp ends made to hold the ends of a glass cartridge fuse. Or is it the clamp ends are what you are calling fuse holders and you're saying that only one end is there????

And it's entirely possible that there might be a screw with no wire on it, as in the terminal that taps off for the rear light. If you don't he a rear light, there will be a terminal screw with nothing under it.

And if, as you say, you know it to have been jury-rigged in the past, I'd urge three things. 1) Take a breath. 2) Check out the diagrams. 3) Trace the wires that ARE attached to the switch, tell us where they're connected and where they're attached on the other end. We can help you, and you can help yourself, but we're not going to get anywhere without knowing what your current (no pun intended) situation is.
 
There is an extra screw on the delco remy light switch, it is to the right of the rear light screw, and one front headlight wire is attached to that screw, the other front headlight wire is attached to the screw next to it. The tail light wire is attached the the lower head light screw. there is no resistor to the screw just above the headlight screw.I think maybe I should buy a light switch from ebay and hope it is more complete than this one!
 
One other thing, on the volatage regulator,it does not say gen, it says L on the tab, the other two tabs say F and BAT. I assume that L is just another name for GEN? I hope this is the right volatage regulator for the tractor! The field wire is connected from the F on the voltage regulator to the F on the generator. The other lead from the generator is connected to a tab underneath the voltage regulator, but it has no markings on it! What is the long tower screw for in the far right of my voltage regulator for? Is it some kind of resistor? It is on to of the field tab on the voltage regulator. thanks, again guys for any help with this! Rich
 
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