At 02:21 PM 2/16/2013, Craig Cowan wrote:
>The left blinker blinks properly until the brakes are applied, then
>the taillight blinks the brake light rather than the blinker. This
>only Occurs on the left side.
>With the flashers on, they work fine, until you apply the brakes and
>the left taillight will blink the brake light.

Without doing a thorough analysis of the schematic, I can tell you
right away to check the grounding on the left taillight with a
voltmeter, and check that the proper size bulbs are installed in all
positions of the taillight (#67 or #89 for the running light, #1156
or #1073 for the other three).  All single-filament, single-contact
bayonet-base lamps.  In both cases I've given the number for the
"heavy duty" lamp first.

It sounds as though you have a bad ground on the fixture and possibly
one or more lamps the wrong rating.  It wouldn't surprise me if
applying the brake would also cause the running light to go out.

If the grounding bars inside the taillight assembly are actually at
ground potential with the fixture lit then it gets more interesting
and complicated.

The taillights ground underneath the ignition coil.

Yours,
David