[TR] TR3 back up light question

[Randall]

> What would be required as far as the wiring goes and hooking 
> up a small back
> up light off the rear overrider bracket on a TR3A?

Depends on whether you want it to be automatic, and how bright you want it.


The simplest version would be a manually-operated light of not more than
40-50 candlepower, which could be a simple switch on the dash (or under it)
with a wire to the power terminal on the fuel gauge (or anywhere else the
"green" circuit can be found, like on the fuse block) and another wire to
the lamp.  Of course, you would need to remember to turn it off after you're
done backing up (which I would forget more often than not).

To make it automatic (ie come on only when reverse gear is selected), you'll
need to add a switch to the gearbox somehow.  If your gearbox is early
enough (I forget the change point offhand), it will already have a brass
plug over the reverse rail.  If not, you'll need to drill & tap the top
cover using an oddball (not normally found in sets) metric thread.  Don't
recall for sure if you need to modify the reverse fork/rail to operate the
switch, but I think not.  Wiring remains the same as above.

For higher power, I would suggest adding a relay.  Wire the switch as above
to one of the coil terminals, then ground the other coil terminal.  One
contact gets a wire to the existing brown/blue wire at the ammeter or
control box; the other contact gets wired to the lamp.

I would also run a stout ground wire from the lamp to a bolt on the body
somewhere.

HTH
Randall