rotary light switch

Farmall H, HV & Super H, 300 & 350, 1939-1958
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dlazyh
Posts: 14
Joined: Tue Mar 27, 2018 5:46 pm
Zip Code: 59330
Tractors Owned: IHC 350U

rotary light switch

Postby dlazyh » Wed Oct 12, 2022 3:54 pm

I will refer to part numbers found on Steiner.com for my new task/upgrade. My 350 has a 3 position switch IHS601, and my plan is to convert to a 4 position switch, IHS599 or IHS788. Both are similar but maybe the IHS599 has the same body? That said I'm guessing that the threaded trunk will be the same size as the original? And I would also guess the extra 4th position is for auxiliary work lights? The reason I'm changing or replacing is the coil on the original switch got very hot, smoking hot! when turned from dim to high beam which may be a faulty switch. And because I have extra work lights installed on the loader/farmhand, I have wiring going to a separate toggle switch and I'm looking into bypassing that. Thank you in advance for any assist on this matter.

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Don McCombs
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Zip Code: 21550
Tractors Owned: "1950 Something" Farmall Cub
1957 Farmall Cub w/FH
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
Circle of Safety: Y
Location: MD, Deep Creek Lake

Re: rotary light switch

Postby Don McCombs » Wed Oct 12, 2022 4:04 pm

This photo and description of the four position light switch decal, from TM Tractor Parts, may help to clarify the four positions on the switch...

http://www.tmtractor.com/new/de/de37.htm
Don McCombs
MD, Deep Creek Lake

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Proud Member of Maryland Chapter 39

The best teachers are those who show you where to look, but don't tell you what to see.
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dlazyh
Posts: 14
Joined: Tue Mar 27, 2018 5:46 pm
Zip Code: 59330
Tractors Owned: IHC 350U

Re: rotary light switch

Postby dlazyh » Wed Oct 12, 2022 6:11 pm

Hi don, thank you for replying. The decal that you submitted doesn't work for me sorry.

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Don McCombs
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Posts: 16723
Joined: Mon Feb 03, 2003 6:45 am
Zip Code: 21550
Tractors Owned: "1950 Something" Farmall Cub
1957 Farmall Cub w/FH
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
Circle of Safety: Y
Location: MD, Deep Creek Lake

Re: rotary light switch

Postby Don McCombs » Wed Oct 12, 2022 9:24 pm

Here is the description from the link...

Decal shown on hood and fuel tank support. This decal was used on McCormick Farmall Cub serial# 115402 and below (mid 1950 and below) with magneto ignition. Used for four (4) position lighting switch L-Low charge, H-High charge, D-Dim light, B-Bright light.
Don McCombs
MD, Deep Creek Lake

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Proud Member of Maryland Chapter 39

The best teachers are those who show you where to look, but don't tell you what to see.
A. K. Trenfor

Jim Becker
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Re: rotary light switch

Postby Jim Becker » Wed Oct 12, 2022 10:25 pm

Your smoking coil doesn't follow. The only time it should have any voltage across it is when on Dim. You said is smokes on Bright. The part numbers you mentioned are all 12-volt switches. If you are working with a 6-volt system, there are other switches.

Assuming it is 12-volt:
There are early 4-posiition switches (like Don pointed out) for cut-out systems. There are late 4-position switches for regulator systems. The decal for them is shown here;
http://www.tmtractor.com/new/de/de39.htm
The "B" and "R" positions both set the headlights on bright then one puts power to the "RL" lug and the other puts power to the "TL" lug. You can connect your red rear light to one lug and your extra work lights to the other. Switches IHS599 and IHS788 both work this way. The difference (I believe) is that IHS599 has lugs with screw terminals while IHS788 has spade connector lugs. I assume you want IHS599. The 6-volt equivalent should be IHS598.

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dlazyh
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Joined: Tue Mar 27, 2018 5:46 pm
Zip Code: 59330
Tractors Owned: IHC 350U

Re: rotary light switch

Postby dlazyh » Sat Oct 22, 2022 1:01 pm

Hi Jim and thank you for your response. The coil on the back of the switch literally started to emit smoke when the headlights were on. I didn't wait to see what would happen if i left the lights on too long as to not create any damage. And to verify, the tractor is a 12v system with no mods.
And I went ahead and installed an IHS594 4 position switch found on ebay. And just by luck, it fit perfectly in the dash, even the notch fit so it wouldn't spin and works as intended. I was even able to use the old knob so anyone looking wouldn't be the wiser of the upgrade.
And about the coil, I've noticed that the new switch coil gets warm when the lights are activated, not sure if that's the way it is but not much else I can do. I've rewired/replaced the old wire to the headlights. From there on to the next repair, sometime! Take care

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Don McCombs
Team Cub Mentor
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Posts: 16723
Joined: Mon Feb 03, 2003 6:45 am
Zip Code: 21550
Tractors Owned: "1950 Something" Farmall Cub
1957 Farmall Cub w/FH
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
Circle of Safety: Y
Location: MD, Deep Creek Lake

Re: rotary light switch

Postby Don McCombs » Sat Oct 22, 2022 2:57 pm

It is normal for the resistance (dimmer) coil to get warm, or even hot, in operation. Your smoke may have been just dust and debris burning off your original switch.
Don McCombs
MD, Deep Creek Lake

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Proud Member of Maryland Chapter 39

The best teachers are those who show you where to look, but don't tell you what to see.
A. K. Trenfor


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