Hello together, one way forward, I suspect no defective glow plugs, or have I already informed myself how I can check them the following: This morning at the start (BC Temp. 7,0°C) briefly the pre-glow symbol in the instrument cluster lit up and the engine jumped immediately after extinguishing the same. Today afternoon at the start (5.5°C) the pre-glow symbol did not light up even after a long wait and the engine was somewhat heavier as expected. In this connection, I noticed (afterward) that my car glows quite rarely according to the symbol in the instrument at low temperatures. When it does that, it jumps easily and immediately after extinguishing the glow turn. I suspect a wobbler or similar in the control of the entire incandation system and no defect of the glow plugs. Is the annealing system controlled outside or engine temperature? Or does it measure the K25 relay? thank you for “hot” tips micha