Blowing Backup Light Fuse

[LCSCHADT@aol.com]

I keep blowing the fuse for my backup light, instruments (tach/fuel guage, &)
on my '87-5ksq.  Some times go a week between events, other times 2-3 times
in one day.  One and only time I've actually noticed the guages go as I
watched, it was as I put it into reverse, and another time (before that) I
replaced the fuse,  started the car, had the guages,  put it into reverse,
off the parking break,  started to back out of the drive, and had lost them
by the time I looked back at the guages.  But it doesn't happen every time I
put it into reverse.  As the "ABS off" light comes on for about a minute
after the fuse blows (and every time one restarts the car until the fuse is
replaced) I think I would have noticed had it blown during initial startup
(when I always check the guages), or if it went while driving - so I'm pretty
sure it is somewhere in the backup light circuit.  I've looked for obvious
frayed wires near backup lights, and near the switch at the manual
transmission and haven't noted any.

Any experience with this one - how likely is it the switch at the
transmission, compared to running all of the wires behind the dash and hidden
in the frame, it seems like a quick and simple thing to try (but how likely
is it to be the source of the problem, how simple, how expensive?).
 Suggestions as to other sources for the problem are welcome - there's alot
on that circuit (fuse #12) involved with instrument guages, warning lights,
and the self-test circuitry.

Sorry if this one's been covered before, couldn't find anything in the
archives through the web site.

Thanks, Larry at lcschadt@aol.com