Smart Forfour Mirror Heating Failure: Fix Guide

I had a similar issue with my Smart Fortwo from 2007, and being somewhat experienced with basic car maintenance, I initially tried checking the basics myself. The mirror heating system stopped working completely during winter. After getting error codes checked, it turned out to be exactly what you are describing. The workshop discovered a damaged cable connection to the heater element in the mirror assembly. The constant movement of the mirrors had worn down the wiring over time. The repair involved accessing the mirror assembly and replacing the faulty connection. Total cost was 95€ including diagnostics and labor. The temperature control system worked flawlessly after the fix, restoring proper winter visibility and vehicle safety. Could you share: Have you noticed any other electrical issues with your mirrors? Does the mirror adjustment still work normally? When did you first notice the heating stopped working? This information would help determine if your issue matches the common failure point I experienced. Mirror replacement might not be necessary if its just the wiring, but proper diagnosis is essential to confirm the exact problem with the heater element.

Last service was at 97710 KM and the mirror heating never worked since then. The workshop initially suspected a blown fuse but that wasnt the problem. The electrical adjustments for both mirrors work perfectly fine, its only the heater element thats causing issues. After reading your experience about wiring problems it makes sense since the temperature control system shows no response at all. Will get the rearview mirror assembly checked specifically for damaged cables. Thanks for the detailed cost breakdown, helps set expectations for the repair budget.

Thanks for the additional details about your mirror heating problem. The timing of the issue starting right after service is interesting, it could indicate the wiring got disturbed during other work. Since your mirror adjustments work normally, this further supports my experience with the wiring issue rather than a complete mirror replacement being needed. In my case, the damaged cable was located where the wiring harness enters the mirror housing, which is a common stress point in our Smart models during cold weather operation. The workshop should focus on inspecting: Wire connections at the mirror base, Cable routing through the door assembly, Heater element terminals The car electronics diagnostic procedure for my repair took about 30 minutes before they pinpointed the exact location of the break. Given your symptoms match mine so closely, I expect a similar repair cost around 95-100€ assuming its the same wiring fault. Winter driving without proper mirror heating can be risky, so getting this fixed before the temperature drops further would be wise for vehicle safety. Let us know what the workshop finds when they check the wiring.

Thanks for all the helpful information about the heating system issue. Seems like the rearview mirror wiring problem you experienced is quite similar to mine. Makes complete sense about the cable stress point, will definitely have the workshop check that specific area during diagnostics. Good call about fixing this before winter driving conditions get worse. Have scheduled an appointment for next week and requested they specifically inspect the wiring harness connection points you mentioned. Temperature control is definitely a safety priority with all the condensation and frost lately. Will report back once they diagnose the exact heater element issue and complete the repair. Hoping its just the damaged cable like in your case rather than needing the whole mirror assembly replaced. The 95-100€ cost estimate really helps set realistic expectations for the work needed.