Reverse Lights Malfunctioning

[avensisch]

I have had my Avensis for 1 yr and have been very happy so far. Recently the reverse lights began malfunctioning. They wouldw work, then stop working, and it seemed to depend on the weather/temperature. I have changed the light bulbs, and this helped once, but they are now not working again with new bulbs. Does anyone have any suggestions before I fork out $$ at a garage for what will probably be a simple solution?

[jamesholden]

Check inside the lenses to see if there is any condensation, if there is it could be the damp from them causing the trouble.

The only other thing I know of is on the really old Nissan/Datsun Micras a sensor in the gearbox packs up which stops the reverse lights working, maybe the Avensis is the same since they are well known for gearbox trouble on the manual versions.