n/s dipped beam bulb total failue
 

I have a 2004 V70 D5 2.4 diesel
over recent months the car has blown bulbs on both n/s and o/s (never both together)
Now the n/s light is not working again but the bulb tests as ok
the fuse in the box under the bonnet also tests ok
there is power either side of the fuse

Can anybody help

That will be a broken wire somewhere! Does the indicator, side light and main beam work on that side? Check all wires for continuity

corrosion in the plug? get a multimeter and stick it in the plug and see if the leccy is getting as far as the plug. Clean off the corrosion with a screwdriver or Stanley and clean with electrical contact cleaner.

If not look for melting/shorts/ cuts in the wire.

if bulbs are failing often you are not using the special volvo long life H7 bulbs ..
You could still have a faulty bulb which works sometimes .. try a new bulb first .

I had exactly this problem. I went to the fusebox next to the steering wheel and the 'headlight' fuse was intact, I was surprised that both headlights appeared to be on one fuse given that a blown fuse could make driving at night a little 'exciting'. Anyway, having done a search of the forum I quickly realised there is another fusebox under the bonnet helpfully marked 'FUSES' in big letters. Despite having the car for 10 years this box (in full view) escaped my eagle-eyes....so to cut a long story short the culprit ie blown fuse lay in there so 'Black Thunder', as we comedically know her, has her eye-sight restored unlike me!