Sir Malach . . . . .
How about some more info, to be gleaned from the unit . . .?
Initially, the heavy blue banded end is being the diodes cathode / negative terminal end.
It looks as if the diode unit has overheated to the extent that it is expelling its potting agents from each end of its axial leads.
One might assume that the unit still possibly could be functional, but with its having overheated to have produced these appearances. Or the diode now may just be a shorted junction.
How about measuring the diode with a DVM in its DIODE test mode and tell us how many millivolts of Vf that diode junction is reading.
If it’s still having a good junction, that reading will further reveal to us if they happened to have employed a low voltage drop Schottky diode in that position instead of a common silicon diode.
Some typical values would be up in the 600-700 millivolt range for common diodes or 190-250 millivolts for Schottky or down in the 500-600 millivolt for fast switching silicon diodes .
I tend to sort of suspect this particular diode function as merely being used in a unidirectional power carrying utilization
The damnedest thing about your pic . . . if being all BLOWN up for better viewing . . . is that you can clearly see the two round vias that the diode leads are mounted within and a very clear view that there is being a wide foil going upwards from the bottom via and it then passes under the bead of the diode.
At the top via it also looks as if a like width foil is being routed downwardly ?
I can’t see the justification, if this uses only 12VDC, but see if there might be a spark gap split, crosscut across that foil in the center. To explain that otherwise direct shorting oddity . . . or just reinspect and be my eyes for me, to confirm...
The upwardly REFLECTED light from the board precludes any closer examination of the photo . . .fill us in.
To answer the “ HOT DIODE “ situation. I would initially want to know the Vf reading that you are going to get across that diode and then that will confirm if there is still a good junction and not a dead short.
Then if the unit still works on the tractor, install the board, but be able to have access to taking readings across that diode. If not possible, use wire leads to remote out connections to be able to do so. Permissible, because nothing other than a static DC voltage is needing to be made.
Hook up your meter in its DC millivolts range, as this time, your equipment will be supplying the test voltage, in order to estimate the Vf being present across the diode at each stage of testing..
Then you keep an eye on the meter at the time. . or any involved delay time . . . as you put the tractor into each of the functions that this board is being responsible for.
At each test transition, IF the millivolts reading rises, that function is pulling MORE current through the diode, find which machine function causes the greatest current demand upon that diode.
Then you need to track the foil paths from both leads of that diode to see if they might happen to end up at a pull off male/female spade connector.
If so, then that would provide a VERY convenient point to make an open circuit to insert your DVM in its SEPARATE 10 AMP test lead connection and place in its 10 amp DC range to actually see what current is being passed thru the diode.
What say ye . . . .
73’s de Edd