Brake lights stuck on unless I wiggle the pedal, so I assume that the microswitch need replacing. Other threads here suggest Omron part number D2HWBL221H is the one (pictured below). It has three connections, whereas another picture I saw here looks like it has just two. An answer would be gratefully received! I have not "gone under pedal" yet and would prefer not to until I have the correct part and have summoned up the will to do it! Thanks.

 

I took mine to Consolidated Auto Works (in Portland, OR.). Have it replaced by a professional and you'll likely never have to worry about it again.

 

It probably needs adjusting. The mounting nuts may be loose.

 

The original microswitches have three connections. One of the switches is wired up as normally open and the other is wired as normally closed. This means that each switch use two of the three connections, with the third connection unused. As long as the replacement microswitches are the correct dimensions you should be fine.

Personally I would do it the other way around and remove the brake switch assembly before ordering the replacement parts to be sure the replacements are correct. You might even find you don't need new switches.

 

The self adjusting RATCHET is a plastic toothed mechanism.
Adjust the switch assy and your brake switch problem will like be solved.