BMW 8 Wiper System Failure: Relay vs More Serious Issues

Hey there! I had a similar issue with my 2018 BMW 5 Series diesel (520d) last quarter. The wipers completely died just like yours, no response in any mode. Turned out it wasn't the relay but rather a corroded connection in the wiper motor wiring harness. The technician found that moisture had gotten into the main wiring connector near the motor, causing intermittent connection issues before it completely failed. They had to replace the entire wiring harness assembly and the motor control unit. It wasn't a quick fix as they had to partially disassemble the cowl area to access everything properly. Not trying to worry you, but this isn't something you want to leave unattended, especially with wet weather. The electrical issues can spread if moisture keeps getting in. I'd suggest getting it checked at a shop that specializes in BMW electrical systems. My repair needed specialized diagnostic tools to properly identify the fault codes. Best of luck with the fix.

Thanks for sharing your experience! That's really helpful, the wiring harness issue sounds quite similar to what I'm experiencing. Would you mind telling me how much you ended up paying for the whole repair? Also curious if you've had any other electrical gremlins pop up since they fixed it? Thanks!

Hey again! Good news, my issue got resolved much more simply than initially expected! Took it to the mechanic last week and they confirmed it was indeed just a faulty wiper relay like you suspected with yours. The actual problem turned out to be a loose cable connection to the relay component, which they fixed up pretty quickly. The total bill came to 95€, which was a huge relief considering I was worried it might be the entire wiring harness! Since the repair, the wipers have been working perfectly, no other electrical issues whatsoever. It's been such a relief, especially during recent rainy weather. This was way cheaper than my initial repair back when I first replied to you, and honestly, it's probably worth checking the simple stuff like relay connections first before assuming the worst. If your symptoms are similar to what mine were, you might be looking at a similarly straightforward fix. Let me know how you get on with yours!

What a relief to hear back from you! I actually just got my car back from the mechanic yesterday. You won't believe it, it was also a relatively simple fix! The technician found a blown fuse and a loose connection in the wiper motor circuit. They cleaned up the connections, replaced the fuse, and did a quick system test. Only paid €120 for the whole thing, which feels like a steal compared to what I was imagining. The wipers are working perfectly now, both in manual and auto modes. Really glad I didn't jump to conclusions about needing major repairs. Makes me feel a bit silly for worrying so much, but better safe than sorry with these electrical issues. Thanks again for sharing your experience, it really helped me stay calm about the whole situation. Guess sometimes the simplest explanation is the right one! Best decision was taking it to a new mechanic this time. They were upfront about everything and didn't try to upsell me on unnecessary repairs. Think I've finally found my go-to shop for future issues.