From memory the original set up used single filament bulbs (lamps) in both headlights. On main both headlights were on . Operating the dip switch caused the offside light to go out and the nearsde reflector was pulled down to the left by a solenoid,the bulb did not alter.Presumabley your wiring harness is set up for that. A highly questionable arrangement , now illegal ?,as 2 approaching cars with the same set up only had their offside sidelights to indicate their width. I altered my father's TA , AKS880 where are you,to both headlights dipping by fitting another dipping reflector in the offside shell and bodging the wiring.The solenoids used to chatter like crazy because the battery was knackered and as soon as the battery was discharging the solenoids let go and the lights would revert to main,blinding the oncoming traffic, a bit like modern self aligning lights. Hope this helps Posted by Peter Martin 02/08/2013 15:56:48