The hoses between the tank and hood nozzles are also heated. There's a small resistance wire in there, take a peek and you'll see it. It's run by the same thermo switch as the heaters in the side view mirrors.

So the thermostat in the washer tank fails? Mine might have, it gets quite hot... hot enough to make the washer fluid steam.

I don't see the system being able to cause any battery drain, it's all run off of switched power so with the key off the system is off. And it doesn't use much power. I seem to recall the service manual saying it all draws under 2 amps.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.