Headlight switch wiring

sony224422 · Jan 15, 2014

I have a converted h with 12 volt with electronic ignition and was working on wiring the head light switch. From what I've gathered, the two terminals that are tied together with the spring resistor are for the regulator which I don't need because I have my alternator excite wire on my ignition switch. But every diagram shows a square switch where as I have a circle switch. I am not even sure if the feed for the switch is correct as it was done by the pervious owner. I also have the switch on the right head light as well. Is that to have seperate head lights or for adding a tail light?

John T · Jan 15, 2014

Bob M or janicholson or others can correct me if I'm wrong, but I believe that big coil resistor is the headlight dimming resistor (used on tractors with a Voltage Regulator NOT a cutout relay) unlike the flat wound field current control resistor used on the LHBD combination light and charge control systems.

John T At the Florida Flywheelers

Bob M · Jan 15, 2014

You have an aftermarket switch!

The OEM switch is more or less square and the terminal screws go straight into the rear of the body. And the coil on your switch is the dimmer resistor for the front lights. (Note a generator field resistor has more turns of fine wire wound onto a flat piece of mica)

Looking at your 2nd photo, it looks like the hot (supply) is the terminal at the top of the switch. The terminal at 9 o'clock would be for the front lights. And one of the two lower terminals is for the rear light.

Correctly wired all lights will be off with the knob turned left. In the center position the fronts will burn dim; the rear bright. And the right position has all lights will burning bright.

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Tip: The resistor coils gets HOT when the lights are burning dim! Be sure no wiring touches the coil with the cover installed. Otherwise heat may burn thru the insulation and cause unpredictable results(!)

sony224422 · Jan 15, 2014

(quoted from post at 09:38:51 01/15/14) You have an aftermarket switch!

The OEM switch is more or less square and the terminal screws go straight into the rear of the body. And the coil on your switch is the dimmer resistor for the front lights. (Note a generator field resistor has more turns of fine wire wound onto a flat piece of mica)

Looking at your 2nd photo, it looks like the hot (supply) is the terminal at the top of the switch. The terminal at 9 o'clock would be for the front lights. And one of the two lower terminals is for the rear light.

Correctly wired all lights will be off with the knob turned left. In the center position the fronts will burn dim; the rear bright. And the right position has all lights will burning bright.

----

Tip: The resistor coils gets HOT when the lights are burning dim! Be sure no wiring touches the coil with the cover installed. Otherwise heat may burn thru the insulation and cause unpredictable results(!)

Thanks for the tips. I am going to try to do a special LED conversion. I have the switch on my bench and I will try those terminals. Do you happen to know what the voltage would be across the resister for 12v? I could solder in a new resister too if I want

Bob M · Jan 15, 2014

Seems to me the terminal voltage with stock headlights and the switch set at DIM is about 9 - 10 volts.

Your LED lights will draw MUCH less current that stock incandescent lights. Consequently the resistance value of the existing resistor is gonna be way too low.

So you'll need to experiment and figure out a suitable series resistance value for the new LED lights.

Incidentally if you do this, please post back the new resistance value (I want to do the same and stick LED's on my Super M someday!!)

Jim Becker · Jan 15, 2014

You may have an aftermarket switch. But it looks just like the later (O D B R) switches from 1958 and on. Does it have 4 positions? Which lug is what may depend on the actual source of the switch. Are there any letter markings next to the lugs?

gene bender · Jan 15, 2014

You have an after market sw and the resistor is for dim lites you will just need to use a meter and read the voltages from the sw to find out where the wires go to the lites you dont need a wire from that sw going to the gen as you have an Alt. You came across someones changing stuff and didnt know what he was doing as that sw is not for replacement unless you know how to wire it.

sony224422 · Jan 15, 2014

Thanks for all the replies. I have determined that the way it was hooked up must of been incorrect. It doesn't do anything except all 4 terminals in the last position. All the other positions don't produce any voltage with where the feed wire is now. I am going to try to use my meter and ohm out to figure out where the feed is supposed to come in

Jim Becker · Jan 16, 2014

The lug at 7 o'clock in your second picture is probably power in. The red wire is probably connected to the headlight lug. The other 2 should be rear light and tail light in one order or the other.

sony224422 · Jan 18, 2014

(quoted from post at 23:03:26 01/15/14) The lug at 7 o'clock in your second picture is probably power in. The red wire is probably connected to the headlight lug. The other 2 should be rear light and tail light in one order or the other.

This is correct. I have the switch figured out. I ended up removing the original resister, and used a 10 ohm 25 watt in its place. I am running a hair over two Amps for leds so it brings them down to about 9.5 volts which looks nice at low power

Headlight switch wiring

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