Agree with several above,
...that would be wise to avoid WD40..
.....while it will of course work at least temporarily,
.......and is at least diagnostically helpful..
........due to the complex distillate components..
..........some of which will leave residues
...........that with heat, oxidation, and electrical arcing..will tend to potentially lead to carbon tracks that can be variably conductive pathways for errant current flow...and not always where you would wish---shorting or unanticipated "switching".
..Contact cleaner of various names including previously mentioned as well as "Color Tuner Cleaner/lubricant" that was once common to clean TV manual channel switches, or simply "Electrical Contact Cleaner/Solvent" are highly volatile--low residue and generally more uniform distillate fractions or mono component solvents, or halo-carbon solvents, somewhat analogous to brake cleaner solvents,...to solvate the carbon and metal oxidant residues of copper to copper or copper to carbon/platinum/tungsten/alloy/etc (like "points").. without leaving a residue for further "arc-tracking" creation; some leaving a non-conductive oxidation resistant lubricant film etc.
...of course this will not cure the pitting and surface loss from oxidation/arcing, but often restore reasonable function with whatever solvable variably conductive/insulative contaminants/pollutants/tobacco residue that can be removed or at least disrupted/broken up/..
...Such solvent mixtures are generally great for other rheostat/tuner/switches...like "un-scratching" old volume/balance/tuner controls on old car radios and such (even easier with movable electronics equipment where you can orient the switch shaft vertically)..spraying down the shaft accompanied by rapid turning of the switch to improve the surfaces, remove gradue/grime/dust/etal--often resurrecting without disassembly..
..did the 2001 TDI NB today; could not find my old can of contact cleaner equivalent--must have used it up rebuilding generator and/or spa pump motor..
...so tried silicone lube spray, at least generally non-conductive--though may have an undesirable petroleum distillate carrier for future residue problems;
...was not the turn signal stalk/switch (no change); but immediate improvement with spraying in the crack at the top edge of the emergency flasher switch and working in by rapidly working the switch...
...Annoying that something as simple as a flasher mechinism/description/location/discussion/.. is not even listed in the Bentley VW Service Manual index!! Turn signal bulb/switch/indicator and emergency flasher listing, but nothing about the flasher itself..
...did not feel like firing up the old computer that has the bentley CD manual on it (and of course not in the "glove box" owner's manual)..
...about as bad as indexes for software packages or Windows manuals.........every entry except the simple or fundamental item you are looking for.
...by feeling the click of the flasher through my finger on the emergency flasher switch, I assume the flasher mechanism is built into or attached to this switch..
....why should one have to look to a forum for such a fundament question; like the conventional standard flasher replacement on conventional systems--just within reach up under the dash, where you can either see, or locate by its click---but of course nowadays, no obvious vision location with a panel blocking access from below..
vent....vent...vent..
