On the above mentioned vehicles a blocked condensed water drain hose can cause a short circuit in the electrical booster heater.
The function of the electrical (PTC) booster heater in the heater unit can be significantly degraded by a blocked condensed water drain.
Due to the fact that the condensed water is not drained to the exterior, there is a risk of an electrical short circuit. In an extreme case there is a risk of a cable fire.
The problem has already been addressed by the vehicle manufacturer, the vehicles checked during a recall campaign and the drain hose/drain valve renewed.
It must be assumed, that for a variety of reasons not all vehicles have been checked and/or repaired.
Please take this information into account, particularly in relation to complaints about poor heating performance.
Important safety note
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