1984 xj6 questions

This forum looks kinda dead but here goes.
My sister just bought a 1984 Jaguar xj6, and as I susspected it has some problems.(she doesn't check things out, and as I am the "familly mech. I get stuck with the problems") my first question would be what options came with these cars? My next question pertains to the first, there is this black "brain box" thing that looks like some kinda ancient cable access box in the trunk that is disconnected. I traced the wires to the glove box but nothing is on the other end....?any clues as to what this thing is? I can't seem to find any good links or sites for these cars for some reason, if anyone could suggest some with tech info (i.e. recalls of any sort, parts services, and general info) it would be greatly appriciated. I have tons of experience on cars but the most I have done on any type of jaguar would be the body work on a friends replica. (not even close to the real car if you ask me) thanks in advance

for a good link on info on these cars you should visit jaglovers ( www.jag-lovers.org )
for the wiring no clue ?????

Try to get a catalog from John's Cars in Dallas. He is the premier engine swap kit source, but also has many improvements for suspension, brakes, etc. and genuine Jag parts for about half the dealer price.