[embee]

Just seen this thread, and as usual the Sid advice is spot on.

Just for info, the reason they work when just clicked on but then go out again as you pull the brake further is that the design of the switch has a "make-and-wipe" feature in the geometry of the contacts. In other words, when the switch goes over-centre and clicks the contacts closed, they first contact at one point then as the little button moves further the contact points move sideways slightly. This is intended to help keep them clean. However what happens is that when opening again they tend to arc a little, causing some burning and contamination of the metal surfaces around the initial contact point but not exactly on it. Thus the circuit gets made at the "clean" initial contact point but when it moves onto the dirty area the circuit is broken and the light goes out.

I've had a couple do this, both have been cleaned up and lubed with dielectric grease and are still working. WD40 seems to work well without having to take the switches apart.

If all else fails, they are cheap enough!