Light won't switch off fully even when I fully the knob (till it clicks). You don't press it in or out. It was working for years without a problem, so I installed a new dimmer, but same problem. Any help is greatly appreciated as it's baffling me

John O, October 2009

Try temporarily replacing the dimmer with an ordinary switch and see if the problem is still there - then you can determine whether the problem lies with the dimmer or elsewhere.

Adam, October 2009