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Yanmar B15-3 wiring diagram??

Posted: Wed Aug 23, 2023 7:18 pm
by Fil
Bit of a long shot as I know it's not exactly a classic, but has anyone got a high Res image of a Yanmar B15-3 mini excavator wiring diagram they could share please?

Some kind person bodged the wiring to the ignition switch and I need to know what should go where.

I found a few pics of the diagram on line, but they are all low resolution so when you zoom in it becomes illegible...

Thanks in anticipation :thumbup:

Re: Yanmar B15-3 wiring diagram??

Posted: Wed Aug 23, 2023 8:13 pm
by essexpete
If you don't have any luck it should be reasonably straight forward. There should be a live in, then wire/s to switched live (possibly via fuses) to components like fuel shut off solenoid, hydraulic isolator, possibly lights. The next stage (and under spring back part of switch) would likely be heat and finally the live to the starter relay or solenoid. Someone with more idea than me might be able to confirm/expand.

Re: Yanmar B15-3 wiring diagram??

Posted: Wed Aug 23, 2023 10:28 pm
by Fil
It's a right mess in there! The switch that's on it now isn't the original one. It only has four terminals, helpfully labelled 1,2,3&4. The new Yanmar switch I've bought has 5 terminals labelled 17,19,30,50 & A/C.
The old switch has 5 wires going to the 4 terminals (two of the wires are crimped together into one female spade connector. Four of the wires look like the original ones that go into a four pin connector block, but the extra wire heads off into the loom with another stray black wire.
All very confusing! And I don't much like mucking about with 'lectrics at the best of times!!

Re: Yanmar B15-3 wiring diagram??

Posted: Sun Aug 27, 2023 12:07 am
by Fil
Well I managed to find and download a manual for an earlier B15 digger and I was able to confirm which wires go to which of the 5 terminals on the new switch. I cut the old female spade terminals off the wires, crimped and heatshrinked (heatshrunk??) some ring terminals on in their place and connected them up to the new switch.
And to my surprise everything worked as it should. Phew!
Once I fitted the new starter motor she fires up first flick of the key. My digger has always been very reluctant to start so it's great knowing that I can get her to start so easily at last :thumbup:

Re: Yanmar B15-3 wiring diagram??

Posted: Sun Aug 27, 2023 5:43 pm
by Jeremy Rowland
Fil wrote:Well I managed to find and download a manual for an earlier B15 digger and I was able to confirm which wires go to which of the 5 terminals on the new switch. I cut the old female spade terminals off the wires, crimped and heatshrinked (heatshrunk??) some ring terminals on in their place and connected them up to the new switch.
And to my surprise everything worked as it should. Phew!
Once I fitted the new starter motor she fires up first flick of the key. My digger has always been very reluctant to start so it's great knowing that I can get her to start so easily at last :thumbup:


Always a good feeling when a repair is successful. :thumbup:

Jeremy