|
possibly worn out wiring, its not uncommon, its exposed to moisture from your windscreen and potentially heater core if its starting to get perished, combined with fresh air and heat = corrosion.
the switch runs via a relay, it could be this that is dead. on a RHD car you will need to drop the drivers kick panel and you will see the relay there, on a LHD it may be you need to drop the glovebox, or maybe they relocate it to your drivers side, not sure of course as we dont have LHD here.
__________________
|