dash lights dimmer switch prob.

My a/c fan heat illumination lights looked to of blown a bulb or 2 so I replaced them even though they looked fine, still only can get 1 bulb to work at a time, no matter how many or which of the 4 sockets I put it in, also since replacing them the dash lights now will not dim, go black once I try to dim from the brightest clicked position (the second position down not the one that puts on dome lights). Any ideas?
99 4x4 LT
thanks,
Joe
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