[Mgs] Oil Pressure question

[Simon Matthews]

I would be willing to bet that the trailer problem was not with a
bulb, but instead a bad earth. Bad earths can cause all kinds of
strange behaviour in lighting systems -- what may happen is that there
is a current path through the indicator bulb, to ground and (since
ground is not connected to the vehicle ground) from ground  in the
reverse direction through the brake light circuit (or through whatever
actuates the trailer brakes).

Regards,
Simon

On Mon, Jul 28, 2008 at 1:54 PM, Bob Howard <mgbob at juno.com> wrote:
> Bill,
>   This sounds related to the question someone asked Car Talk on
> Saturday, the guy out west who asked why the electric brakes on his
> trailer went on whenever he switched on his 4-way flashers.   The
> suggestion was that he had a bad lightbulb in one of the flasher
> fixtures. It will be interesting if he gets called back for Stump The
> Chumps to learn what the cause was.
>    What would be the equivalent for you---the OD lockout switch, the
> reverse lamp switch?
> Bob