Lawn Tractor headlights are burning fast

[NorMichRes]

Hello to all! This is my first post, so please let me know if I mess up. Last week while snowblowing my driveway, I lost one of my headlights. I didn't think much about it at the time, because I've had this tractor for about 5 or 6years now without any problems. The very next night when I went out to clear some more snow, I lost the other light. The next day I went on line to Sears Parts Direct, and when I saw the price of $20 plus per bulb, I almost fell out of my chair. I called around to the local auto parts stores, and found that NAPA has the bulb for $8.79. I stopped by, and picked up two new bulbs, and put them in my tractor. Yesterday, was the first trial run with the two new bulbs. I spent about one and a half hours clearing snow, and when I covered the tractor for the night I know that both bulbs were still working. Today we had another 6 inches of snow, so I started the tractor, and when I turned on the lights, I noticed that one of them is already out. I have a Craftsman DLT with a 20 horse Kohler twin cylinder engine. The wiring for the lights looks fine, and when I checked the voltage to the lights last week, I think it was 12.4 v. Do any of you have any ideas? I've seen some information about these chinese made bulbs that suggests that they won't withstand the vibration, but if that's the case, how could the originals have lasted so long?

Thank You in advance for any input.

 

[aczlan]

do the lights turn on if you wiggle them in the socket? at work we have a Cub Cadet where the RH bulb turns off unless you wiggle it in its socket.

Aaron Z

 

[Blagadan]

You said you checked the voltage to the lights, was this with the engine running?

 

[Philscbx]

these chinese made bulbs won't withstand vibration, how could the originals have lasted so long?

1. We didn't have to put up with so much china junk before until the last few years.

2. What's the model # of bulb?
Is there more vibration with what's being used?
May have to upgrade to skid steer style flood lights that have halogen bulbs.
The price you paid sounds like they were halogens.

3. You may have the voltage, but if the current is low, halogens require full power to keep from burning out.
Usually upgrading the wire to the lights can make a difference to at least 14G.

When they were working, did they dim at idle and bright at full throttle?
Were meter readings taken when it's running, lights on, at the battery at different rpm?

 

[SnowRidge]

Some, but not all, Kohlers are equipped with voltage regulators.

Kohlers without a regulator have a low output alternator that slightly overcharges the battery. It has a separate lighting coil that provides power to the headlights only when the engine is running. It either works or it doesn't. Unregulated lighting coils provide just enough power for two headlights, but if one fails, the voltage to the other one wil rise and it may burn out, too.

If you have no switch for your lights, or the lights won't come on if the engine isn't running, you probably have an unregulated system, and you can disregard the rest of this post. If you can turn on your lights with the engine off, the rest of this post should be applicable to your engine.

Regulator equipped Kohlers use shunt voltage regulators. Shunt regulators work by turning excess alternator output into heat. Unlike the field regulators typically found in automotive applications, a failed shunt regulator results in full unregulated output from the alternator, instead of no output from the alternator. The result is an excessively high voltage delivered to the battery and the electrical accessories. High voltage will burn out the lights.

On my 25 HP Kohler, the regulator is mounted on the lower part of the fan blower housing, with its finned heat sink protruding into the air stream inside the housing.

You may have a failed regulator. To test it, start the engine and measure the battery terminal voltage after it has been running a couple of minutes. If it is working properly, the terminal voltage should be around 14.5 volts. If it is significantly higher, the regulator is bad.

Running the machine with a failed regulator will eventually kill the battery.

Kohler service manuals provide only limited help in diagnosing electrical system problems, as they rely on special factory testing equipment that must be purchased from Kohler.

Note: Kohler also mounts the rectifier in the same module as the regulator. If that part of the assembly fails, there will no or reduced output.

 

[NorMichRes]

The bulbs that I purchased last week at our local NAPA store. are halogens. The bulb number is 889. They are identical to the originals that I pulled out. After I posted last night, I did some more research on the net and found that this bulb is also used in automotive fog lights, forklift headlights, etc... I have a bad feeling about that regulator issue that you mention snowridge. Mine is in the same spot as yours, so I will follow your directions first thing tomorrow morning. I didn't mention this before, but when the original bulbs burned out, my ammeter gauge was fried at the same time. I didn't want to replace that until i was sure that the bulbs were going to be okay. Now I'm glad that I waited. Thanks to all who replied to my post. I have always believed that you can never have to much information.

I'll be back to reply again tomorrow.

 

[artfull dodger]

I do know those bulbs do not tollerate vibartion very well at all. Buddys car is always loosing a fog light that uses those. Usualy the filiment is laying loose inside bulb. I cant stand these new tractor lights on lawn tractors, the old seal beams used in the 70's and 80's on cub cadets ect did so much better and lasted longer. Check the voltage at the lights with the engine at full power and see what it is. Mike

 

[NorMichRes]

I finally had a chance to check the voltage from the regulator, and it reads 14.6 volts from idle all the way to wide open. We've been getting dumped on with snow in the last few days, so I've been using the tractor every day. Yesterday I took a close up look at the two bulbs that I recently installed, and the one that burned out, was broken off at the base of the bulb. The other bulb is still working, so maybe I'll get lucky, and it will last for many years to come...

Thanks again for all the advice.

 

[grurban]

It will help their life time if you wear cotton gloves when installing. Hand grease will produce a hot spot on the glass and shorten it's life.

Gary

 

[pinetree10]

Reviving an old thread -

My 2008 JD1332 snowblower was built with a headlight that comes on whenever the snowblower is running. I wish they had put in a switch for it because I rarely use the machine when it's dark outside but that's how they built it.

Anyway the headlight bulb seems to be blowing out fairly frequently in recent years and I don't know if it's because the bulbs can't take the vibration or if there's something wrong with the voltage going to the light. Anyone have any experience with this sort of thing? I've replaced the bulb probably five times now in the ten years I've owned it. I don't remember this being an issue when the machine was new. It seems like it's happening more in recent years so that leads me to believe either the bulbs are getting more cheaply made or something might be wrong with the electrical system.

It takes a Sylvania 881 halogen bulb and I never touch the bulb, only the base. At this point I just put some electrical tape over the connection and taped it under the control panel so it's out of the way and protected from the weather. If I have to use the machine in the dark I have a new bulb in a drawer to plug in when I need it.