M4030su electrical

[TomCxyz]

I installed an electric fuel pump on the M4030su to replace the failed mechanical fump. Initial tests (key on & glow plug) were Ok - fuel pump ran. Went to startup, turned key to glow plug position, heard some faint frying (electrical arcing) sound in the console / dashboard or maybe from engine compartment. Now all electrical function of the key switch are inop - no glow plug dash light at glow plug position, no fuel pump run at key on, no starter motor run at start position. Also, turn signals and tail lights don't work. Seems that main 12v to key switch might be lost. Not sure why lights are also inop because they used to work even at key off position.
Checked the four fuses in the fuse block ; they are not blown. Main 12v feed to fuse block is live. Not sure what else might be basic electrical test point. Don't have a wiring diagram.

What sort of electrical component faults might be checked for troubleshooting ?

 

[GreensvilleJay]

1st, have you the wiring diagram of your tractor ? You really need that to properly diagnose WHY you have problem.

How did you wire in the fuel pump ? Did you install an inline fuse ? How much current does the pump use ?

 

[TomCxyz]

Don't have a wiring diagram. Found a diagram for a M4500 (https://kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/&file=M4500 electrical wiring diagram 2 pages ex WSM.pdf), but I dont think it is close enough to M4030su to be helpful.



The fuel pump is operated from a 30A relay with a 30A fuse on the relay input side from the fuse block. Not sure what the amperage on the fuel pump is ; id guess 10A or 15A, I'll try to look that spec up somewhere.



Attached pic shows the firewall wiring harness and devices with labels for items that I think I have correctly identified. Two relays / boxes and some yellow plug caps are labeled with "???" ; I'd like to know what those are - your educated guesses welcomed.

+++update

Found a diagram that illustrates the firewall electrical components :

https://ku-part.com/kubota/catalog/m4030su-tf-854/9578/60944/

The two firewall "???" items in the attached photo are :

35800-75070 RELAY,STARTER
35533-75290 TIMER GLOW LAMP

That only leaves in question (???) the two yellow plug cap items at lower left. Don't see those yellow caps in any of the other electrical part diagrams :

https://ku-part.com/kubota/catalog/m4030su-tf-854/9578/

And, this new info doesn't shed any light on where the main key switch 12V feed is or why it's dead.

=====

 

[GreensvilleJay]

I 'think' new members need to post 3 or 4 msgs before you can attach files ??
try replying here 3-4 times, then see if you can ??

 

[TomCxyz]

I 'think' new members need to post 3 or 4 msgs before you can attach files ??
try replying here 3-4 times, then see if you can ??

I've made ~10 replies between this thread and another one.

I was able to upload a pic file using computer. The upload problem had something to do with the phone I was using.

 

[TomCxyz]

Not having success locating a downloadable M4030su WSM or just the electrical diagram. Any ideas if the M5030 is similar to the M4030su ?

https://tradebit.com/#gsc.tab=0&gsc.q=kubota m5030

https://kubota-parts.servicemanualvault.com/Kubota-M5030SU-Tractor-Parts-Manual.html

I noticed that some manuals (WSM, Operator) descriptions list M4030, M5030, M6030 as covered models.

https://ebay.com/itm/394231319680

https://peacefulcreek.com/products/...s-owners-manual-operation-maintenance-adjust

 

[TomCxyz]

May be a similar situation to https://orangetractortalks.com/forums/threads/m9540-want-crank.59473/post-579146
Corroded connections somewhere.