Hi there, today I sorted the problem out. I positioned the light switch in the middle position ie "0", then turned the ignition on and operated the high beam for 12 seconds. Then released it and turned the ignition off. The dipped beam does not come on again after that whilst the position of the switch is on "0". Hurray, at last I can drive my S60 D5 without having the lights on all the time, just when I need them. I live in Greece and it is very bright here all the time so At last I have a choice now. I hope it helps others.

thanks lads, its supposed to be a self bleeding system so no priming pump. other have mentioned a need for bleeding at times as mentioned by simon and number cruncher. but its turned out that my problem relates to the stop solenoid electrical circuit. its actually registering as earth?? as far as i know its supposed to be live with ignition on. by applying live to it does click. so any info on the electrical circuit of the stop solenoid would be greatly appreciated.

"polycarbonate is difficult to bond onto"

Indeed. And it scratches very easily - not really the ideal material for headlamp lenses!

One thing that's always worth checking on these, is the security of the connexions on the fuel-rail pressure sensor located in the bottom of the fuel rail. Unstable primary [low] pressure on the live-data is usually a failing in-tank pump. As already said; look for copper-coloured particles in the filter housing - if you see any, change the complete housing/filter as an assembly. Don't try and clean them out; you really don't want any of them getting into the secondary pump.

If the low-pressure side was showing good pressure, but the secondary [high] pressure was fluctuating; then there is the possibility that you have an internally-cracked injector leaking excessive amounts of fuel back to the tank.

The 406 glow plugs. 8mm flex screw driver and magnetic pick up tool 12 mm deep socket for 1 & 2 , the one behind the pump I made a spaner from an old 12 mm 1/4 drive socket .
weld a piece of flat 2mm by 10 mm an 250 mm long the side only use a small socket aprox 10mm deep drill the socket with 10.5 drill to allow thread through. this will give enough room to undo 1 flat at a time. bend the flat to a step then a curve. I have a 8 mm socket on outher end to do wire bolt. You can test plug in head but have yo take wire of first. Then check with meter to batery. But may as well take out as so much work getting wire off. Anouther tip put nuts in socket with piece of paper towel stops them falling out of socket as you thread them through all the pipes. I use magnetic pick up tool to fit nut on no 3,4 just a fiddle.