I would guess at the relay or possibly the switch. The sides will be on all the time, you must be getting a feed to the switch for the low beams to come on. As it's both mains then it's unlikely to be bulbs or holders at fault. Try swapping some relays around, it's not likely to be an earth problem.
Enoch.

not something silly
 

Saw some of your other posts and noticed your working your way round the whole wiring system . Also noticed your doing this without the ignition circuit wired in and on some cars there is a dimmed dip relay system wired into ignition circuit, its not a fault along these lines is it?

Bob

many thanks for that i will try that in the next few days
thanks again

you could have your dip main relay terminals mixed up so your feed is on dip and your dip wire is on the feed terminal :)
hope that makes sence
feed should go to dip then coil pulls on switching to high if you swith dip and feed terminals the all goes out when high is turned on