Help! L3240 won't start when cold

[firebird93]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

 

[bferris01]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

Thank, I am running out of things I can check, I am going to have to try and get a buddy over with more skills than I have.

 

[bferris01]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

How did you get the socket off the bar that is is attached to in the dash? I moved the cluster but can seem to get it loose to double check it. I tried a small screw driver but it didn't release. Any tricks?

 

[pepper66]

Bferris.
From the picture of the relay I could only tell you how it works. I can't clearly see the terminal numbers, but I can tell by the terminal blade sizes. The large blades carry the current from power to the glow plugs. Power may be battery+ or switched ignition. I would say probably battery + or always hot. The smaller terminals energize the relay. I'm not sure how a Kubota operates without looking at a wiring diagram. On an auto one of the small blades would be ignition + and the module or dash cluster in our case would complete the circuit. I can look at the wiring diagram on my M59 tomorrow, it may be similar. I don't think the power to the large blades would go through the ignition switch, that is probably too much current for the switch.

 

[firebird93]

How did you get the socket off the bar that is is attached to in the dash? I moved the cluster but can seem to get it loose to double check it. I tried a small screw driver but it didn't release. Any tricks?

sorry i don't remember the details. that was 2 tractors ago. i just remember it was in the dash behind cluster and what i finally discovered
i wish you best of luck. i know it can be frustrating.

 

[pepper66]

Bferris
I looked at M59 wiring diagram. Your relay is in the same location as mine, look like a similar setup except my instrument cluster is on the right rear fender. The large blades, one to glow plugs, the other to battery + 12 volts all the time. The two small blades, one is hot 12 volts with ignition on. The other goes to the cluster and supplies the ground or - to the relay this completes the circuit and allows the relay coil to energize. Dont not connect anything this wire to test it, except a high impedance voltmeter. The circuit from cluster to relay is a very low current circuit. If you can fell the relay click

 

[pepper66]

If you can feel the relay click when you turn ignition on the cluster circuit is ok.

 

[bferris01]

Thank everyone, I am back to work at the firehouse for next 48 hours, so I won't have chance to trouble shoot it again for a bit. I will update what I find, thanks for all the thoughts.

 

[moship]

The pin numbering scheme for the relay from the Grand L40-3 WSM is shown in the first picture.

2nd Picture:
I've also included a picture of a Glow Plug wire connector above the oil filter area that is an easy location to check the presence of battery voltage. Simply disconnect to remove the Glow plugs from the circuit, so the voltage can be tested. (The OP also has this problem posted on another forum and he doesn't have this connector. I'm including the info in the event it helps anyone else that may have this connector. Perhaps the difference is that I have a cab model (L4740-3) and the OP is ROPS. It's also near impossible to isolate the glow plug power supply at the buss bar because of the AC compressor and bracketry being in the way. The voltage can NOT be measured with the glow plugs in the circuit.)

3rd Picture:
The last picture is of the 50 amp slow burn fuse for the Glow Plug power feed (Relay Pin 1). This wire then runs to the relay and from the relay Pin 3 to the Glow plug.

If nothing else, this may help others.

 

[RoyKing]

if jumping the relays delivers power to the glow plugs that side of circuit is ok, that leaves mainly the relay and it's primary circuit. So make sure the relay is the right amperage and test primary side with bulb to verify the ground side good. Compare the bulb brightness when connected to known good ground as compared to the ground in the relay block. Cause sounds like you have tested everything except the ground circuit in the relay block.