I just installed a shift light in my 93 ex with a b16 and i used an rpm activated switch, i have everything hooked up correctly. but my tach doesnt read anymore. i unhooked the white wire that is the wire that reads the rpms, i had that hooked to the blue wire behind the gauge cluster and the tach works again, i tried hooking it up to the negative side of the coil taping in to a wire that comes from the distributor, but the tach died again. anyone have any experience with this? any help is appreciated thanks