Vectra - moisture inside headlamp - robZilla
I recently replaced both (dipped) headlamp bulbs on my 99T Vectra (facelift model with the perspex lens). I have since noticed a build-up of moisture on the inside of the offside headlamp. There is none inside the nearside headlamp.

I have checked the bulbs are in properly and at no point did I touch the bulbs with my bare hands while I was fitting them. Does anyone know what might has caused this moisture?

Also how can/should I get inside the headlamp unit to clean the inside, and how can I stop this from happening in the future?

Many Thanks.
Vectra - moisture inside headlamp - bazza
Did you replace the rubber covers if fitted? It may be an unrelated crack in the perspex or even a faulty seal around the unit itself (can be cured with clear silicone sealant). Take the bulbs out and dry the unit thoroughly with a hot air gun or hair dryer. That usually cures it.
Baz
Vectra - moisture inside headlamp - robZilla
Thanks bazza, I did replace the rubber covers. I will have a go at removing the unit and drying it out.
Vectra - moisture inside headlamp - Victorbox
I used to dry a damp Mk1 Cavalier headlamp out before sealing the edge by driving around for a week or so with the cover at the back of the headlamp off. The heat from the engine bay plus free movement of air into the headlamp was enough to dry out the inside of the glass. This might avoid the hassle of removing the unit just to dry it.