Originally Posted by Splitrock
One of mine is not working. Is that a bulb in the back? I don't understand how it works.
The tail light monitors are "fiber optic", which is plastic wire, if you wish.
Light travels thru plastic wire. If you cut the wire, you cannot easily splice it back to gether, so that it would continue to transmit light.
If one end of the optic wire is place against a light source, that will show at the other end of the optic wire.
The tail light monitor is nothing more than a optic wire placed behind a tail light bulb. The other end goes to the monitor indicator that's on the side of the trailer.
When the tail light bulb lights up, that light then shows at the other end.
Again, cutting a fiber optic wire is a bad thing, because the two cut ends must be put back together again,perfectly mated, which is near impossible,