S6 total meltdown

[env]

Got into a 2008 Audi s6 this morning - horn stuck on, lights flashing on and off, all wipers going like there is no tomorrow, dash going for an early Christmas tree impression. It did however start....

Any ideas? Rained heavily overnight so presuming it’s water ingress related. Disconnected and reconnected battery, no change.

It’s off to garage tomorrow, but always good to be armed with some ideas.

Env

[RammyMP]

Yes, sounds like it’s got a bit moist! Good luck!

[annodomini2]

Something's shorted, look for blown fuses

[Timmos1974]

Is the passenger footwell wet?

[seyre1972]

Check the ECU box/plenum. Had similar on my old B7 S4 (crack in plastic had let water unto box, which had several relays under the ECU). Mine would keep fan running until battery was flat when switched off.

Luckily I had found an entry on a US Audi forum which had exact same symptoms as mine - showed to the indi Audi garage whom replaced it.