how is the new switch ran ? where are the constant power's and grounds ran too on the affected components ?

i would check all connections, make sure all grounds are connected to factory ones or directly to the chasis and well.. grab a voltameter and test all of the wires that have current and trace the drop in voltage.. it sounds like you may be drawing too much current or have jostled a wire in the switch install. if this doesnt help any let me know.