These switches can be refurbished if the unit isn't damaged or contacts are too worn beyond repair.
Dismantling:
Remove the 5mm nut with long nose pliers. Check each removed part for extensive wear. Use a Dremel type motor with a rotary wire brush to clean and polish the contacts and spindle shaft.
Re-assemble:
Observe all spring loaded tabs make contact. You may have to bent the tab a bit for firm contact.
Apply lock-tite type sealant on the nut thread. Tighten the nut lightly with the shaft in the pull out
( lights on ) position.
Operation and continuity check:
Connect an Ohm meter to the switch terminals and rotate / pull to check operation and continuity.
Oil shaft with light oil . Spray a bit of WD-40 inside the switch if operating it is noisy.
