OK -
Per 1990 FSM...
The cigar lighter feeds off of the "Radio" fuze (15A, Blue, #2)
The cruise control module seems to get power from the "Gages" fuze (7.5A, Violet, #17) There is also an inline fuze (4A, "Taped to cruise harness near fuze panel) that you'll want to check - it supplied power through the multifunction switch on the column. The wires in and out of that fuze are pink, 14 gage, and runs between the brake lamp switch (at the top of the brake pedal) and the multifunction switch (on the tree.)
The cigar lighter should only work with the key in ON or ACC - not with the key OFF. Just so you know...
5-90