my xj 550 dipped headlight is flickering and dim at idle and low rpm, but if i blip the throttle the light brightens til the revs drop off. same happens on the motorway. the main beam is unaffected and is bright across the entire rpm range. also, i have no headlight on turning on the ignition, until i have started the engine... is this normal? the tail/brake lights are unaffected as are indicators and dash lights....
any help on this would be greatly appreciated