1990 SC w/ stock suspension, 34k or so miles on it, so suspension is not at all worn out: when ARC is set to firm, its fine. when ARC is set to normal mode, something from the rear clicks 3 times (either ARC computer, or an actuator i think) and the FIRM light blinks 3 times every so often. other than the clicking and blinking light it rides fine in either mode, but kinda freaks me out. any ideas what it is? actuator? ARC computer? bad connection somewhere?