[xj] Sovereign cruise control

Thanks to fellow lister Dennis Smith, my 84 Sovereign now has NO defects!
The non-functioning cruise control was a result of a faulty cut-off switch
at the brake pedal. Dennis was able to check all the other switches for me
using his multi-meter (must get one of those). We stopped when we found the
dead switch. Fortunately, I had a spare switch picked up from a wrecker
(see, you never know when the “pack rat mentality” will prove useful). The
cruise control works beautifully, sets, cuts out, resumes and hold the set
speed. Thanks Dennis, and to all the others for suggestions.