There are several issues with the heater fan. If you turn on the first operating mode and do not hear a relay click near the passenger's feet — it is an issue with wiring or the relay. There is no power supply. Or, the blower motor has failed.

If there is a click but the fan does not spin at low speeds but starts spinning at high speeds — this indicates an issue with the resistors.

There are two bolts to the left of the driver's feet that hold the part we need.

It is likely something like this happened there

There are two solutions. Either buy a new one (still available), or solder it. But this is not an easy task.

Attention! The version with climate control and just the heater have different resistors, and they are not interchangeable.