Modus Windshield Washer Heater Fault

Sounds familiar. I had similar issues with my old Opel Astra. Check the connection to the heating element. The washer motor was fine in my case. Is the washer fluid reservoir heater working?

Where exactly is this heating element located? And how can I check if the heating element is working?

On my Astra, it was near the washer fluid reservoir, integrated into the nozzle assembly. Use a multimeter to check for voltage. Honestly, though, I'd just take it to a workshop. It's likely a corroded connection. Save yourself some grief.

Thanks, I'll check the voltage, but you're probably right. I took it to the shop, and it turned out to be a defective plug connection as suspected. Repair cost 95€.