L2350DT 4x4 Glow Plug Question

[mcnuttja01]

L2350DT Glow Plug Issue, I get a light on the console when key turned to LEFT, but there is no voltage at the glow plug. Disconnected Hot wire from Glow Plug and zero volts. Is there a relay some where??

 

[GreensvilleJay]

sadly kubotabooks.com doesn't have an L2350 WSM,so I can't look at the wiring diagram ( owners manuals SHOULD have it, but none do...)
I suspect there is a relay. Follow the wire back from the glowplugs and see where it goes. Since a light comes on the dash, power is getting past the switch,so switch should be good.

wiring diagram would be real nice though. perhaps someone can post it ?

 

[Flintknapper]

Look to see if you glow plug 'indicator' gets red hot when you hold the key to the key to the left for 30-45 seconds.

No relay in that circuit that I can see. Power goes through the indicator to the glow plugs.

 

[PoTreeBoy]

L2350DT Glow Plug Issue, I get a light on the console when key turned to LEFT, but there is no voltage at the glow plug. Disconnected Hot wire from Glow Plug and zero volts. Is there a relay some where??

Are you sure that's the preheat indicator? According to the Kubota parts list, the L2350DT has a glow indicator. This is a small coil of resistance wire that's in series with the glow plugs, which glows when current flows. If it's glowing with no current at the glow plugs, there must be a short to ground between the indicator and the glow plugs.

 

[mcnuttja01]

Look to see if you glow plug 'indicator' gets red hot when you hold the key to the key to the left for 30-45 seconds.

No relay in that circuit that I can see. Power goes through the indicator to the glow plugs.

I appreciate the response, but It can't get hot if it has zero volts.......

 

[mcnuttja01]

I appreciate the response, but It can't get hot if it has zero volts.......

Do you have a schematic of the circuit??

 

[Russell King]

As I understand what you have (from these posts) is a very simple system that is similar to an L185. I looked on line to find the INDICATOR for the L2350

then I looked up that part number and see an INDICATOR

So it appears to be a very similar system to what I am familiar with = nothing but wire really.

the wiring is battery positive to the starter. There is an additional red wire on the starter terminal that goes to the key switch. It may go through the fuse block but will end up as the power feed to the key switch. There should be a constant 12 volts to the key switch, then the key switch will power only the glow plugs in one position and the starter solenoid will crank the engine in another key position. In that position the key switch should also provide power to the glow plugs (but it probably bypasses the INDICATOR).

So figure out if you have 10 or so volts to the glow plugs wire (use battery negative terminal for the ground point) while cranking the engine. The release the clutch pedal to stop engine from cranking and the voltage should be near 12 volts. Don’t hold it on very long because the glow plugs are not really 12 volt parts so will get really hot really quickly. That is not really god for the glow plugs.

If you get voltage to then that wiring and key switch position is good.

Then you can test the glow plug INDICATOR wiring if you want to. You have to get to the back side of the indicator and see if there is voltage to both sides of the INDICATOR. The side from the key should be 12 volts, the other will be less since the INDICATOR is really a resistive load that should glow in a dim or dark environment (not visible in bright sunlight).

You probably need a new indicator and glow plugs but report back what your results are for better advice. Your INDICATOR is EXPENSIVE compared to what I paid for mine.

Good Luck.

 

[North Idaho Wolfman]

You have the WSM, envelope top right.
The glow plugs are fed from 2 switch positions.
Path 1: Is Pre heat , from switch through the glow Indicator then to the glow plugs
Path 2: Is crank, it from switch to glow plugs.

Wiring diagram are on M.10-5
Glow plug paths are on M.10-7

 

[mcnuttja01]

You have the WSM, envelope top right.
The glow plugs are fed from 2 switch positions.
Path 1: Is Pre heat , from switch through the glow Indicator then to the glow plugs
Path 2: Is crank, it from switch to glow plugs.

Wiring diagram are on M.10-5
Glow plug paths are on M.10-7

View attachment 150669

Thanks for the info and diagram. Based upon the diagram in the Pre-Heat position, The only way I could have a Lit Indicator and no voltage at the glow pugs is if it is grounded down circuit from the Indicator prior to the Glow Plugs. Correct??

 

[GreensvilleJay]

Based on the diagram. nicely supplied by NIW..
if one (or more) of the glow plugs is 'shorted', then yes, indicator lights up and no voltage to the plugs.

i suggest disconnecting all the glow plugs and measure them. Typically they are about 1 ohm each.
also while diconnected, put voltmeter to the 'feed wire' , turn key to 'preheat', you should get 12 volts.

 

[Russell King]

Thanks for the info and diagram. Based upon the diagram in the Pre-Heat position, The only way I could have a Lit Indicator and no voltage at the glow pugs is if it is grounded down circuit from the Indicator prior to the Glow Plugs. Correct??

You are correct that the indicator must be grounded on the low voltage side for it to glow.

That ground path is normally through working glow plugs, but could be a short in the wire or a defective glow plug that has zero resistance. I think it would be possible for a ground path back to the key switch on the crank wire but that would probably cause other problems. I guess the indicator itself could have failed and is shorting directly t ground through the case.

sorry for redundant information but @GreensvilleJay types faster than I do!

 

[mcnuttja01]

Based on the diagram. nicely supplied by NIW..
if one (or more) of the glow plugs is 'shorted', then yes, indicator lights up and no voltage to the plugs.

i suggest disconnecting all the glow plugs and measure them. Typically they are about 1 ohm each.
also while diconnected, put voltmeter to the 'feed wire' , turn key to 'preheat', you should get 12 volts.

I had already performed your last test of the feed wire disconnected from the glow plug and I have zero volts when the switch is in Pre Heat position. Tomorrow I'm going to "pull" the dash and trace the wire. It's got to be shored and/or a Switch problem..........

 

[North Idaho Wolfman]

When you turn the switch to glow, the glow indicator (heating element) glows?
Your not talking about a Light bulb on the dash right?
If it is the indicator, How long does it take to heat up?
If it's quick then a glow plug or wire is shorted.
But if the wire to the glow plugs was shorted when you when to start it would melt that wire or more likely blow the fuse link above the starter.

 

[PoTreeBoy]

When you turn the switch to glow, the glow indicator (heating element) glows?
Your not talking about a Light bulb on the dash right?
If it is the indicator, How long does it take to heat up?
If it's quick then a glow plug or wire is shorted.
But if the wire to the glow plugs was shorted when you when to start it would melt that wire or more likely blow the fuse link above the starter.

Yeah, he needs to check the key switch also. Sounds like he's up to it .

 

[Flintknapper]

When you turn the switch to glow, the glow indicator (heating element) glows?
Your not talking about a Light bulb on the dash right?
If it is the indicator, How long does it take to heat up?
If it's quick then a glow plug or wire is shorted.
But if the wire to the glow plugs was shorted when you when to start it would melt that wire or more likely blow the fuse link above the starter.

GP indicator on mine (same tractor) will visibly heat up (red) in low light in about 20 seconds.

 

[Russell King]

GP indicator on mine (same tractor) will visibly heat up (red) in low light in about 20 seconds.

Is this a correct statement for your tractor? = There is no light bulb that indicates the glow plugs are heating.

 

[North Idaho Wolfman]

Is this a correct statement for your tractor? = There is no light bulb that indicates the glow plugs are heating.

Yep no GP light bulb on that model.

 

[Flintknapper]

Is this a correct statement for your tractor? = There is no light bulb that indicates the glow plugs are heating.

My L2350DT has two lights on the dash that indicate the glow plugs are preheating AND a GP indicator ( a spiral resistive wire) that will glow red (hot) if the key is held in lefthand position long enough.

 

[Russell King]

My L2350DT has two lights on the dash that indicate the glow plugs are preheating AND a GP indicator ( a spiral resistive wire) that will glow red (hot) if the key is held in lefthand position long enough.

That is interesting but confusing to me. On my L185 the key-switch has four positions Off, Run, headlights low, headlights high. There is a separate switch that that operates the glow plugs when turned left and the starter/glow plugs when turned to the right.

The oil pressure light and charge light are on when the key is turned to the on position so the lights have no indication on the glow plugs, but do indicate that power is ready to be applied to the glow plugs. Once power is applied to the glow plugs then the glow plug indicator will glow (in dim light)

Please explain how your key switch operates and how it applies power to the glow plugs.

 

[North Idaho Wolfman]

My L2350DT has two lights on the dash that indicate the glow plugs are preheating AND a GP indicator ( a spiral resistive wire) that will glow red (hot) if the key is held in lefthand position long enough.

View attachment 150709

View attachment 150712

I hate to disagree with you but the only reason the lights come on, on the dash have nothing to do with the glow plugs, it's a light test so you know they are working.
Later models they called it the easy checker system.
Look at the schematic there is no glow plug to dash wiring.