Light Switch Information

Wed Jul 17, 2013 9:45 pm

Getting around to wiring the lights on my now 12V '48 Cub. Last night I individually tested each bulb and socket and we're 3 for 3. I have (what I believe to be the original) switch from the tractor. I cleaned it up a good bit for better connection and am getting continuity to two posts in two positions.

But since the light switch is on the workbench, it's kind of hard for me to know what the switch is supposed to be doing. I believe this is a 4 position switch? Is that Off, headlights, rear light, and all three? What position is which? I'd settle to just use the original switch and have all three lights come on at once. After all, I don't plan on doing much in the dark on this tractor anyway. But I would be tickled if I could get just the headlights and then all three lights.

I saw a diagram Rudi posted earlier, but it was for a 6V. Mine has a 6V switch, but I believe the diagram showed a wire going back to the generator. I was planning on just putting the switch in between the line from the battery and the lights.

Re: Light Switch Information

Thu Jul 18, 2013 5:17 am

On a 4 position switch looking at the dial from the front. Turning clockwise the first position is low Charge, the 2nd is high charge,3rd is lights on low and forth is lights on high. I hope this helps. I am not sure whos diagram this is to give them credit but I thought it may help.

Re: Light Switch Information

Thu Jul 18, 2013 5:21 am

After rereading your post I see what you want to do. (just use it as a simple light switch). I think if you connect a hot lead to the fuse position and the feed to the light from either of the light positions that would work.

Re: Light Switch Information

Thu Jul 18, 2013 7:01 am

Very helpful diagram - Saved it offline, so when I reassemble my 48 - I can use this and the photos I took of this area. Always great information here. Thanks to the poster :D and original developer :D

Re: Light Switch Information

Thu Jul 18, 2013 9:39 am

I assume you have figured it out already, but with a 12 volt conversion you will not have the F (field) lead, so the first 2 positions will both simply be off. the third position will be dim lights (may cause the resister to smoke with 12 volts), + the real light will be on. Last position will be bright lights + rear light.

Re: Light Switch Information

Thu Jul 18, 2013 8:56 pm

John and All,

Thanks for the info. I never would have guessed about the low charge and high charge. You'll have to tell me more about that one. I am pleased to be able to save the old switch though. Will keep more of the tractor together and save me about $35 for a new switch.

Re: Light Switch Information

Thu Jul 18, 2013 9:17 pm

On tractors with the 4 position light switch, the generator only had a cutout that disconnected it from the battery when it stopped charging. There was no regulator. The field lead from the generator went to the light switch and the operator selected either low charge by switching in a resister between the F (field) lead and ground, or high charge by directly grounding the F lead.

Re: Light Switch Information

Fri Jul 19, 2013 2:40 pm


What made the operator select a different charge modes? I never considered the the electrical system keeping itself maintained would have anything to do with a light switch.

This is all very fascinating to me. And also makes me very glad that I switched over to a 12V one wire alternator.

Re: Light Switch Information

Fri Jul 19, 2013 3:37 pm

Regular operation uses the Low charge setting, such as a full day of plowing. When the tractor was being used for short periods the high charge could deliver a full charge in a much shorter operating time. In my case, when I am plowing snow, running down the road etc., I always use the high charge setting cause my flashing light runs off the battery.

Re: Light Switch Information

Fri Jul 19, 2013 11:46 pm

Just to bring this thread home, I wired in the lights tonight. I ran the taillight wire and the headlight wire to the "headlight" terminal. Flipped the switch and sure enough, resistor started smoking. I was able to get a little "low" and "high" beam action though. Didn't like the smoking, so I removed the resistor and now just have a simple all on position at the last click.

Don't know as to when I'll ever have need to use these lights, but who knows..... atleast they'll be there then.

Re: Light Switch Information

Sat Jul 20, 2013 9:02 am

To add a little to Rudi's explanation, the Low charge was approx. 2 amps and the high about 11. If you left it on high for extended periods of operation it would overcharge the battery and boil acid out of it, so the operator needed to think about how long it would be running. My mowing tractor is usually left on LO most of the time since it runs for longer periods without being shut off. The grader tractor is always left on HI, since it rarely runs more than 30 minutes at a time, and the same with the loader. As a further note, when the lights were on the switch set the charge to high, since the lights drew about the same amount of current as the generator could produce.