OK.
I'll suggest some things to check. Hopefully others will chime in to help also.
Just to be sure we are talking about the same engine, could you provide the catalog number of the engine?
I would guess that the short did something to the engine and not the tender. That said, have you tested the tender to make sure it is all Okay?
Can you provide some details as to what you have tried and what results you had? For example, when you did the engine reset, did the horn sound and the head light flash, etc.?
We'll start there before I provide a bunch of other things to check/do.
Best,
Dave