(ET) Sometimes it's that simple

[The CZ Unit <cz alembic crystel com>]

My E20 was doing something odd after a day of hauling stuff in the back 
woods. Speeds 1-3 were fine but as soon as I went to speed 4 the tractor 
would drop out. No voltage drop on the meter, just drop out. If I sat 
there for a moment it would come back when I re-applied the throttle, 
then work, then drop out again.

Worse in D1,D2 gear, fair in L, almost never in LL. So I drove out in 
LL, got to the shed, then it dropped out again. Realized the problem:

The seat was slightly hung up on the lip of the battery box. So when I 
went to speed 4 (which usually has a bit of a lurch) the seat switch 
would open up and drop the contactors.

Oops. :-)