Komatsu d20 starter electrical problem

[Robert Jesurun]

Had a bad starter and got it rebuilt. I have entire wire harness removed from machine and am working in garage. With all batteries conected to starter I can only get starter to spin by jumping it at starter. The switch will not power starter. In checking with a meter none of the wires are carrying any voltage yet the starter has voltage at its terminals.

 

[wbvs58]

Sounds like you haven't got the low current side of the circuit earthed or back to the negative. I take it that you are just bench testing things.
Ken

 

[Delmer]

That would be "grounded" back to the negative. Also, Japanese machines can have start relays much more complicated than what you see on average equipment.

So are you testing the starter, or the whole harness? "Jumping it at the starter" are you jumping the big terminal to big terminal or big terminal to little solenoid terminal to get it to spin?

 

[mitch504]

See the post in the section for D21 thread about the safety relay from the alternator, This could well be your problem

 

[Robert Jesurun]

Sounds like you haven't got the low current side of the circuit earthed or back to the negative. I take it that you are just bench testing things.
Ken

Not sure what you meant ken? I have dash and switch out and all are on bench, and wired to bateries and starter.