BMW 3 Brake Light Issue: FRM Short Circuit Fault 1

Yes, the 'FRM: Short circuit fault 1' code could be causing the taillight issue. Start by checking the wiring and connectors for any visible damage or corrosion that might be causing a short circuit. If everything looks fine, you may need to reset or reprogram the Footwell Module (FRM) using a diagnostic tool. If you're not comfortable doing this, it's best to have a professional mechanic handle it. Let me know how it goes or if you have any further questions!

What tool could I use for that??

You can use a BMW-specific diagnostic tool like the BMW INPA software or a more general OBD-II scanner that supports BMW modules, such as the Foxwell NT510 Elite. These tools can help you reset or reprogram the FRM. Make sure to follow the instructions carefully. Let me know if you need more guidance or if you have any other questions!