If the bulbs have power going to them you must have an earth fault. I suppose you have checked the bulbs themselves?

Might be a poor connection. you would still see power but at such high resistance the lamp would not work.

I have found the plastic multi connector plugs the culprit in the past. either found by following the wiring diagram from the fuse box or a bit of examining all connectors and just prising them apart and reconnecting, often just the effect of the contacts moving against each other is enough to give them a little clean and hey presto it works again.

Good luck