Turn Signal Problems After Battery Change? Get Help!

Hello dear members,

I'm in a bind. The old battery in my A3 1.8T, which is a 1997 model, died over the weekend because of the car audio system.
Today, I bought a new battery, a stronger one with 70Ah and 630A.
It starts now, but the turn signals, windshield wipers, and lights are no longer working. I've checked all the fuses, and they seem to be fine.
Could it be due to the large battery?
Are relays involved? If so, which ones (part number)?
Please help urgently!

Greetings everyone, thank you.

[Translating...]

I think this might be your problem:

/viewtopic.php?t=8739

Please don't be bothered by the fact that it says "Golf 4" above. In this regard, it's exactly the same as the A3.