Electrical Gremlins

["Kim Boydell" <boydell@domain.elided>]

I saw two posts concerning weird electrical manifestations in the last Alfa
Digest and thought I would pass on a story of a friend's Ducati 125.  It
seems that he had real problems getting his brake light to work.  When ever
he stepped on the brake pedal the headlight came on.  He traced the wires
for hours and could not find any way that the brake light circuit could
effect the head light.  After many months of this he mentioned it to another
motorcyclist who said it was obvious what the problem was, the tail light
bulb was in upside down.  Apparently the brake light filament wasn't taut
and when the bulb was installed upside down it would rest on the tail light
filament.  Consequently, stepping on the brake pedal sent current through to
the brake light filament to the tail light filament and on to the headlight,
which them was illuminated.  There is no substituted for experience.

By the way, many warning lights in Alfas are fail safe, that is current
keeps the light off, not on so that a failure of the sender, a short
circuit, blown fuse etc. will cause illumination. (I discovered this when my
exhaust temperature light came on when the car was cold - blown fuse)

Regards

Kim
_________________________________
Centre for Economic Analysis - Canada Inc.
http://www.home.istar.ca/~boydell

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