What Model and Year of Vauxhall is this?
Have you inspected the bulbs/holders on that side?
it is a 04 model Combo 2000 DTI
Normally on these same as the Corsa C chich the Combo is based on you have the large "double in one relay" yellow in colour,the early vans had 2 but im sure these had the single double..the relay covers boths sides - id imagine you have checked up at the back of the engine bay corner..just next to the passenger side bonnet hindge or under the windscreen . there should be relay box there ..the box or BCM.you normally see the wiring loom travel up along the top side of the inner wing through the plenum and lead to that box ..you need to remove the cover over the top,once off then relay is yellow right near the front..but you should also inspect the bulb holders too and ensure the bulbs are in contact..I do hope this helps..If you have anything further you need to ask then please do so before you rate