(ET) Ideas please - E15 reverse only

[Darryl McMahon <darryl econogics com>]

It's been a hectic summer and fall, and I'm about to head off to other 
tasks.  Here's my situation, and I'm hoping it sounds familiar enough 
for someone to be able to offer a logical next step.

E15 was running OK in the fall.  Got parked outside for a bit, and key 
switch was left on for a 2-3 weeks (got called away when originally 
planning to put the snowblower on).  Life doesn't seem to care much 
about my priorities.

There's also evidence of mouse presence in the front battery compartment 
(new for me).

I put the snowblower back on this morning.  When I put the tractor in 
forward (when I discovered the key was still on), it moved in reverse. 
Putting the tractor in reverse also moves the tractor in reverse.  Front 
lift works, PTO works.

Tractor is on charge now, and I won't get back out to it until tomorrow 
(optimistic) or the next day (more likely).  My hope is that a full 
charge and having the control circuits off for a few hours might help. 
But not counting on it.

Any thoughts or guidance as to what is a likely cause for tractor moving 
in reverse when forward speed is selected?

Thanks in advance.

--
Darryl McMahon
Freelance Project Manager (sustainable systems)

Check out the laundry microfibre catcher at:
https://contest.techbriefs.com/2020/entries/sustainable-technologies-future-energy/10412