Temperature setting on shower valve

Hello

I have a problem with my shower thermostat. Only two temperatures can be set. Once very cold and once the temperature of my hot water heater. No lukewarm... Nothing at all. Can anyone help me?
Regards

Hello,

sounds like a mechanical fault in the [Wassermischelement].

However, more precise information can most likely only be provided by a plumbing specialist on site, or possibly the manufacturer’s telephone hotline if you describe the type of [Armatur] and the problem.

A proper remote diagnosis via the internet is almost impossible.

Regards,

Dirk