#7 fuse blown, no brake lights - 1987 245 DL

[myspv]

#7 fuse (stop/brake lights) keeps blowing. so, no brake lights.
before i dig in i thought i would see if this is a common problem, maybe particular to the wagons(estates).
if no one has any ideas i think the first place i will check is for frayed wiring insulation around the hinge for the hatch. i can't think of other wires that would get stressed so much. i'll let you know what i find.
(aside: i know i should always check the easy thing first, but for some reason the first place i headed was to check for continuity at the switch behind the brake pedal. at least i know that part is fine.)

(approx. 265,000 miles)