I own a Mercedes C180 - 2005 model.
The onboard computer reported a "faulty mirror right turn indicator" fault.
As far as I know, there are no fuses for this problem.
I was quoted South African Rand 4,000 (equiv UK Pound 380) to have the LED unit replaced!!
I decided to attempt fixing it myself.
1. Position the mirror as far as possible down and inwards.
2. Search for the release spring behind the top part of the mirror.
3. Unclip mirror and pull off mirror heating wirers. Stow safely.
4. Take the entire mirror housing and bend/flex it towards the rear of the car and towards the driver/passenger window.
5. Feel for the release clip - it is situated on the engine side of the mirror unit. Push clip with screwdriver and slide off outer mirror casing. It might need a little force to initially come off ---- not too much.
6. Note the position of the turn indicator connector plug on the mirror unit and on the LED unit. This was my problem. The connector plug was either corroded or connections were loose. I sprayed the connector with some anti corrosion/water repellent spray (Q20) and pulled/pushed connector plug a few times.
7. You may also unclip the LED unit from the mirror housing and test it.
8. Reassemble in reverse order taking care that everything fits back into position.
Hope I saved you some bucks!