|But why are both bulbs dim?
What we have now is an extra lamp added to the circuit.
in series with the taillight.
In a series circuit, the voltage, is
divided between the loads.
The lamps are 12 volts bulbs but, there is only have 6
volts across each bulb,
this is why they are both dimmer than usual.
Did we actually fix the problem or is there
one still present?
As soon as we remove the test light and replace it with the
correct fuse back in the circuit,
the resistance of the circuit goes back down and 12 volts
is then again placed across the
tail light and it glows brightly again.
The reason for this explanation is so that you will realize
that just because you cleared the
short in the circuit does not mean the test light will go
out when the problem is fixed.
It is a common misconception and if you don't realize it,
then you might assume that the problem
persist and keep on looking for a problem that doesn't exist.
Common wiring shorts are from pinched wires within a harness
or through openings of
a engine case, component, or insulation has rubbed off and
exposes a bare wire that touches the
frame or engine case. Retracing your steps after a bike modification
or moving a wiring harness
around will sometimes quickly expose where a shorted wire
exist and clear the problem.
Your test light can also be connected to ground or the
frame of the bike to feeder wires to
the bikes various components to determine if you are getting
power to said items.
This is how your shorted wiring was repaired
using a test light without the needless
waste of blowing multiple fuses.