We’ve had a question from Gary, who asks about his Massey Ferguson 135 dynamo, as the electrical system isn’t charging the tractor battery. Here is what Gary says…
I have a MF135 with a diesel engine.It has stopped charging the battery and wondered if you could tell me how to check to see if the dynamo and other components are working correctly to find out what is wrong.The tractor is used on a working farm daily as it is ideal to get in the small byres.
Thank you
Gary W.
Hi Gary,
We have written a page on how to test the dynamo on the Vintage Tractor Engineer Site…
Testing a 12V Dynamo
…also from there you can see a link to the MF35 wiring diagram, which is similar to yours (but positive earth instead of negative).
Just a few questions for you to think about
- Do the lights work? When you turn on the lights does this show a minus current? Because if the ampmeter does not show a discharge during electricuse (eg lights on) then it is likely that the charging does not work for the same reason – the reason been that it is possible that the ampmeter has gone faulty. When this happens the battery cannot charge.
- Are your battery leads and wiring loom OK. If it is turning the starter
motor over OK then battery leads should be OK.
- Is the wiring loom OK. Often the earth lead comes off the regulator box (or breaking through at some point).
Hope this helps.
Kind Regards,
The MF135 Team.
