2008 BX 2350 Glow Plugs Indicator Stays on After Starting Engine

[DavidG95]

New BX 2350 owner here. I inherited the machine with around 1,000 hours. The weather has been between 20 and 45 F since owning and after preheating the engine according to the table, the engine will start fine. However, the glow plug indicator remains on throughout the operation and does not turn off. I have not run it more than 15 minutes at a time since coming into possession.

Several questions:

1. Does this indicate that the glow plugs are energized or could it be just a faulty lamp? I imagine this will greatly shorten the battery life of the tractor if they are constantly energized. Is there a way to test this?
2. Quick research has shown that a faulty relay or controller could be the culprit, but most of these threads have been on L series. Does the BX have a relay and controller?
3. Can someone point me in the direction of an OEM diagram that shows what part number is needed, if I wanted to replace the relay or controller?

Thanks for the help.

 

[Eagle1]

Not normal on my BX2200 light is only on when the ignition switch is held in the preheat (glow plug) position. I do not think that any of BX have a timing circuit for the glow plugs, but I have been wrong before.
On mine the glow plugs come direct from the ignition switch with the Dash light in parallel to the glow plugs.

Here is the Operator manual
https://www.ggmgroup.com/wp-content/uploads/2023/11/Kubota_BX2350_OP_Manual.pdf

 

[DavidG95]

Thanks for the reply. I did download that manual and I did not see any mention of a timing circuit.

 

[Eagle1]

I have the BX23 service manual and here is electrical section for it. Not sure if it is the same as the 2350

 

[rScotty]

Not normal on my BX2200 light is only on when the ignition switch is held in the preheat (glow plug) position. I do not think that any of BX have a timing circuit for the glow plugs, but I have been wrong before.
On mine the glow plugs come direct from the ignition switch with the Dash light in parallel to the glow plugs.

Here is the Operator manual
https://www.ggmgroup.com/wp-content/uploads/2023/11/Kubota_BX2350_OP_Manual.pdf

No, it's not normal for that lamp to stay on. It means that the glow plugs are staying on. If I were you, I would pull the fuse to the glow plugs after starting the engine until you figure out why they are not turning off. At least you know that the glow plug warning light is working !

Some of the information you want is in the Operator manual that Eagle1 sent.
On page 11, the picture of the key switch shows there is an owner-selected glow plug position available as you turn the key, and on page 12 there is a chart of how long to hold the key in that glow plug position on cold days.
So instead of having an automatic timer or temperature circuit, on the BX2350 tractor the operator is the timer circuit.

But we don't know if the key switch triggers a glow plug relay or if the key switch is itself acting as the relay. Glow plugs use a lot of power, so that means a there has to be a heavy wire to carry that power. You may be able to tell if the key switch is acting as a relay by looking to see if there is a heavy gauge wire coming from the back of that key switch.

If not, then there will be a wire going to a relay, and then to a fuse, and then to the giow plug itself.

You should eventually get a service/shop manual for your tractor. It will have schematics as well as diagnostic information for all the tractor systems. Those manuals are real specific to each model. You can get them at the dealer, and they are expensive and worth it.

The service/shop manual will NOT have part numbers. For that you need a parts manual for your tractor, and yes, they are a separate manual....and also expensive and probably worth it.

Messicks.com has some part manuals for Kubota online along with part prices, but their site is incomplete and difficult to navigate.

Good luck,
rScotty

 

[DavidG95]

Thank you all for the very detailed responses. I assume the fuse is easily accessible while the tractor is running? I would like to use the machine but I obviously do not want to damage the engine or drain the battery unnecessarily. I have looked at the manuals and the online free version of the the shop manual. I have not found the relay mentioned, so it leads me to believe that the key is acting as a relay. Hopefully when I pop the fuse box there will be a diagram showing which fuse is for the plugs. I will look for the heavy gauge wire when I get a chance.

If necessary I will have the local Kubota dealership take a look. I would prefer to do this myself if possible and not spend the shop rate.

 

[DavidG95]

I should also mention that in the electrical pdf that Eagle1 linked, as well as this shop manual, the troubleshooting guide only has the option of "If the pre-heat indicator does not light". There is no symptom for if it stays on.

https://kubotabooks.com/AutoIndex/i...Manuals/&file=B2050_B2350_B2650_B3150_WSM.pdf

 

[Eagle1]

I should also mention that in the electrical pdf that Eagle1 linked, as well as this shop manual, the troubleshooting guide only has the option of "If the pre-heat indicator does not light". There is no symptom for if it stays on.

https://kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/&file=B2050_B2350_B2650_B3150_WSM.pdf

Does light go come on if you just go to run, not past to glow or start? If not I would be very suspicious of the ignition switch.

 

[DavidG95]

Good question. I will report back on what I find.

 

[Eagle1]

Aftermarket switch
Ignition Switch for Kubota Compact Tractor BX2350D BX2360 BX2370 BX2660D BX2670 | eBay

You can also find them on Amazon...

 

[Tinhack]

Sounds like you have to turn the ignitions switch back to ON. My Ford ignition switch is the same way. There's four positions: Off, On, Glow, Start. If you turn the key to Start then just release it, the switch returns to Glow. You have to physically turn the key back one position to On.

 

[Eagle1]

Never had to do that here but makes sense as possible problem.

 

[rScotty]

Thank you all for the very detailed responses. I assume the fuse is easily accessible while the tractor is running? I would like to use the machine but I obviously do not want to damage the engine or drain the battery unnecessarily. I have looked at the manuals and the online free version of the the shop manual. I have not found the relay mentioned, so it leads me to believe that the key is acting as a relay. Hopefully when I pop the fuse box there will be a diagram showing which fuse is for the plugs. I will look for the heavy gauge wire when I get a chance.

If necessary I will have the local Kubota dealership take a look. I would prefer to do this myself if possible and not spend the shop rate.

Does your BX2350 have a 110v plug for a block heater? A block heater was often a dealer installed option on Kubotas as well as other tractors. They are typically installled in the side of the engine block into the water jacket. often taking the place of a freeze plug.

I do not know if a block heater was availble for the BX2350. If there is one, there will be an obvious 110 volt plug on a short cord protruding from the side of the engine block. Generally you use it by plugging that heater in for an hour or two before starting the tractor anytime the temperature is below freezing.

The reason I mention the block heater is because using a block heater is an alternate - and superior - way to start a diesel engine in cold weather. If yours has such, you could just disable the glow plugs at the head and use the block heater instead. Easier than pulling and replacing the glow plug fuse, and accomplishes the same thing....i.e. gives you a working tractor with the engine protected and time to figure out the glow plug problem.

rScotty

 

[rScotty]

Sounds like you have to turn the ignitions switch back to ON. My Ford ignition switch is the same way. There's four positions: Off, On, Glow, Start. If you turn the key to Start then just release it, the switch returns to Glow. You have to physically turn the key back one position to On.

Not doubting your word, but wondering if the Ford switch was designed that way or just getting old.

After all, why would a switch be designed to default to a glow plug position AFTER the engine is started?

That sounds wrong somehow. It makes me wonder if that old Ford switch has gotten some corrosion in it. Those older Japanese ignition switches were right out there in the weather and luckily able to be disassembled and cleaned up. Could that be it?

Anyway, good catch. Maybe that's the problem with the BX, too.

 

[DavidG95]

I really appreciate everyone's input. I was researching block heaters and it appears to be a straight forward install, even with removing the freeze plug as outlined in this post. Forgive my ignorance, but can you elaborate more on "disable the plugs at the head"? Are you referring to disconnecting them so they are not energized?

 

[DavidG95]

https://www.tractorbynet.com/forums/threads/block-heater-install-project-bx2350.89491/

 

[Tinhack]

Mine is an after market switch and so was the one I replaced. I don't know for sure if it's right or not but that's the way it works. My Kenbota Glow position is different. It has a spring loaded position opposite the On and Start position. You have to turn the key to the left and hold it there for Glow. Then you have to turn the key to the right for On and Start.

 

[rScotty]

I really appreciate everyone's input. I was researching block heaters and it appears to be a straight forward install, even with removing the freeze plug as outlined in this post. Forgive my ignorance, but can you elaborate more on "disable the plugs at the head"? Are you referring to disconnecting them so they are not energized?

Yes, disconnecting them. The glow plugs are connected by a conductive copper strip, and the "hot lead" that powers them when the plugs are energized is the connector (2) in the middle. Here are some pictures from different work shop manuals.

Be aware that the water jacket space behind the freeze plugs is limited. So block heaters have to be made to fit. Get one that fits the BX, and think about the consequences if a poor install leaks coolant.....rare, but it does happen.

 

[DavidG95]

Okay. So my plan to start will be to test the voltage and see if the glow plugs are actually being energized. Can anyone tell me what the voltage should read on a multimeter when the glow plugs are in the preheat mode versus what they should read when the tractor is in operation? I assume I should be testing the voltage on the hot lead that you pointed out, number two

 

[garry1p]

When my glow plugs quit working from the key I just added a waterproof push button switch.

IIRC 12ga wire from battery (+) to fuse to push button to each glow plug. Still working when I sold the tractor 4 years later