1999 Chrysler LHS 1999 chrysler lhs dash lights only work w

i have a 1999 chrysler lhs 3.5 186K my mother purchased the car brand new and i got it with 120k it has been a great car. i replaced the struts and radiator my self. everything else was all done by a certified chrysler mechanics. around 180K the dash lights quick work. everything else works fine the dimmer switch was replaced with a known working one. the guages them self work, just not the illumination lights. every once and a while they work fine. as soon as i shut the car off they will not work for about another week. any help? any illumination relays in the dash or behind the cluster it self? thanks!