355 Fog Light switch

Switch is bad

Has a little spring that pushes a tab for tension, sounds like it broke inside
You can remove the cover and see it pulls off but be careful of stuff flying around, Maybe do it in a plastic bag to catch the parts.

 

It would be safer to release the tabs on the switch from behind. Trying to pry it out from the front risks scratching stuff and possibly snapping the tabs on the switch that retain it. Removing the panel is quite easy. Use the instructions from Stickynomore:
https://stickynomore.com/help.html
Follow the instructions for 355 hvac panel removal and you can take out the rest of the stuff and get to it. Pretty self explanatory, once you get started. Good luck on the switch.

 

You can test by swapping in any other constant on-off switch such as the defrost. As others have said, the plastic prongs at each end if the spring mechanism have broken. There is no repair for this small part. You can offer maybe 65-70 to ferrparts via ebay for a replacement but it will be sticky and will likely not match your other switches (same with a new switch though).

You can swap the top cover to the new switch to maintain the finish but you will need to remove and reinstall the spring mechanism. If you break the prongs, you are back to step 1.

Those prongs would be a good first 3d printer project for the Fcar community. Good luck.
Ken

 

Genius.

I've probably opened 100 various vintage Italian switches and never thought of that.