Rear defogger would work only if the switch was pushed many times and, eventually wouldn't work at all.

Removed switch, cleaned the pins with fine sandpaper until shiny. Unable find my aerosol electrical contact cleaner I then slathered the innards of the switch with WD40 and exercised the switch a couple dozen times. I then rinsed out the WD40 with a few judicious squirts of aerosol brake wash.

Reinstall switch, works perfectly.

Nothing new here. Just a reminder to not go out and buy new parts before without first attempting a repair. The old-car-lover's mantra of "Remove, clean, lubricate, adjust" often brings old stuff back to life.

Cheers
DD

 

Sound advice!

Same goes for fuses and fuse mounts when experiencing strange and anomalous electrical issues