990 electrical

Still working on the case 990 and am making great progress. I
am now running the tractor but have run into an issue. The
dash lights stay on and gas gauge does not respond even
though we were told it worked before the rebuild. Did I hook
something up wrong?

What shuts off the electrical system on this diesel? On my
Massey 40 it is the oil pressure gauge that kills it as when
there is pressure gas gauge works but no pressure no
electrical. Is it the oil sending unit? The tractor is getting oil
pressure.

Any help appreciated.
 
There should be a large brown wire that runs from the starter solenoid to the ignition switch(depending on age, there may be a circuit breaker, or fuse along the way). Power goes outward from there.

The fuel gauge gets switched power from the ignition switch, through the gauge, to the fuel sender. You can check the sender, it will show 0 ohms when empty, and about 40 when full.

FWIW, no DBs after 1960 or so had an oil gauge, just an idiot light that comes on when you don't have 7#. If you have a gauge, I think you can safely assume that you have a cut up wiring harness. Might be bets to get a schematic, and start from scratch.
 
Thanks for responding. The wiring appears to be original with
the idiot light still intact. I just made sure it was pumping oil
through everything before starting. My problem is the lights on
the top of the dash never shut off after the engine shuts down.
Am I not turning key switch off right? I think I am just doing
something wrong. Battery keeps running down.
 
There should be no power through the switch when it is in the position where the key will slide out. Usually this is 1 click short of all the way counter clockwise, but might be all the way depending on the switch.

It is possible the switch is bad, they were made by Lucas.

The green light being on is to telling you no oil pressure, red that it isn't charging, and yellow that the hydraulic filter needs changed. Odds of all three being on is pretty slim.


You need a multimeter, and a wiring schematic.
 

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