Headlamps flickering then quit working, finally solved.

   / Headlamps flickering then quit working, finally solved. #1  


Elite Member
Sep 17, 2013
Most of the YM series, both domestically sold and gray market have the Stanley headlamps and Yushin-Seiki switch.

I had spend about 2-hours debugging the failed light. The bulbs are the halogen type Wagner HM202 that are the direct replacements of the Stanley P15D25 incandescent. The halogens are much brighter per watt and more durable.

Original P12D25

Wagner HM202, direct replacements
HM202 replaces Stanley P15D25.jpg

After testing both, they worked perfectly.

Next was tracing the wire harness, connections, voltages and doing a continuity check on all the circuits.
These all checked fine
- harness and wires
- fuses
- connectors
- VR
- bulbs

The last item to deal with was the switch. The machine was made in 1981. It had late 1970s technology. I was expecting the worse to order a new switch, if I could find one. Took the access panel off, undid the set screw and took the knob off.

The taller and most middle wire supplies power coming from the fuse box.
The other two white terminals are for low and high beam. Sort of cheesy for old tech. It makes the connector just up behind the headlamps a 6-terminal.

The wire with the black terminal and red wire supplies a lamp to illuminate the tach-hour meter.

The tach-hour meter bulb must of been original with the machine. Still works. Just lots of crud nearly making it black over the bulb. Took a few shots of CRC electronics cleaners and a towel to scrub all the grim off.


The Yushin-Seki switch.

Here it is all buggered up inside,

Can't use harsh cleaners either. The trace board is phenolic. The CDC product is made for this material.


Retested and it worked. The machine has lights again.

Then went out to mow the front hwy ditch. I only mow there with all the lights on, flashers and rear work light. Too many nuts on the road.
   / Headlamps flickering then quit working, finally solved. #3  
Amazed to see a switch that looks like it was purposely designed to be disassembled for cleaning.
That's what is so great about the '70's designed Yanmars.

Its very clear that they were thoughtfully designed for simple owner-maintenance by owners who are just practical farmers, not specialized mechanics. And to be maintainable anywhere in the world where there will be no dealer support. I admire this. The founder of Yanmar corp declared his goal was to make food production as easy as possible and subsequent CEO's have maintained that value. Simply a quality product for a better world.
   / Headlamps flickering then quit working, finally solved.
  • Thread Starter
If a person looks at Yushin-Seki over the 50, 60, 70, 80 eras, they made mostly motorcycle electrical parts. Many of the Japan tractor companies used those electrical parts too.


Its possible the Yanmar and Deere tractor keys were made by them as well.


Yushin-Seki made all of the Shibaura (Ford) tractor keys and ignition switches. Likewise for Mitsubishi (Massey), etc.

And why for Yanmar would I take a guess, well, many of our tractor parts come from this Japan car company, ;)
Datsun 70-78 240z, 260z, 280z, OEM ignition switch and key.

And the Ford New Holland keys look very similar to the Yanmar Deere keys of back then.


My 2 keys from the JD850 and YM2610. Both work in every Yanmar and Deere I tried them in. lol
DSCF1718sm 2.jpg
   / Headlamps flickering then quit working, finally solved.
  • Thread Starter
We should start a thread on all of the automotive parts used in our tractors from back then. Not only would it be neat historically, it would also allow a person to obtain parts at 1/2 the cost vs the Ag dealers. Both my VR and the alternator were automotive items at a brick and motor national store chain at 1/2 the cost! I just stated, Datsun (Nissan) 1974 and knew the vehicle as I cross referenced it on Rockauto.com for verification.
   / Headlamps flickering then quit working, finally solved. #6  
My Org. key. The ford key doesn't look anything like it. The JD. Key looks the same as the late model 5103 JD. If I recall correct.
   / Headlamps flickering then quit working, finally solved.
  • Thread Starter
Knowing about the switch and how the wires attache, it's very possible now to add marker lights and parking lights to the rear of the tractor for roadway use. Already have the turn signals.

There is a YM250 model based off the YM220. The YM250 is the European version of the YM220. The YM250 has all of the roadway safety panels and lights. Using the manual, I could see how the roadway schemes are laid out and take a few queues
from it.



If people love their YM220, the YM250 is the deluxe version of it.
   / Headlamps flickering then quit working, finally solved.
  • Thread Starter
Was browsing eBay for info and noticed 3 bulbs going for a mere $17+shipping.

This is basically Ag eBay robbery of the consumer !

That's right, look for the deal and for a BETTER halogen bulb too.

   / Headlamps flickering then quit working, finally solved. #9  
Lots of sellers like that. It always pays to double check other places, as you did.

Rock Auto is one of my favorites, especially if I can drum up an order for more than one item....

All the best,

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