[AT] Tractor lighting puzzler

[John Wilkens]

This is a good one.  I installed two new low beam and two new high beam 
headlights on my MF 175--one each on each fender.  The low beams and high 
beams each had their separate wiring to the light switch.  They are wired 
so in switch position 1 only the low beams come on; in switch position 2 
both high and low beams come on, and in switch position 3 only the high 
beams come on.  The first time I tried them the lights on the right fender 
worked according to plan, but in ALL switch positions the lights on the 
left fender BOTH came on VERY dim--together.  Obviously the right fender 
was not grounded good enough so I added a ground wire from tractor frame to 
the fender--which cleared up the problem..       The puzzler to me 
is--before I grounded the right fender why did BOTH lights on the right 
fender come on (very dim) even with the switch energizing only one circuit 
(high or low beam)??????????????        Electricity always has been a 
"challenge" to this old guy!    John

                    In the wide-open spaces of NE Oregon