Clio starts badly

Hello first of all to my car Renault Clio 2 1.5 dci (diesel) 2001 so for about 3 weeks my Clio makes problems at the start in the morning, the pre-gloss lamp shines continuously, even if the engine is already running. 3 weeks ago, when it was still a bit warmer the lamp started to shine at some point because I thought it will probably lie on the glow candles, so I changed all 4 but did not change anything about the problem. On warmer days it also started normally without problems, the I’m surprised that it’s not due to the glow plugs and now that it gets colder, it starts worse and worse, but if I turn the key 6-7 times back and forth before the start (for annealing), it also starts a little better than usual, but still delayed. Does anyone know what it can be? Oh yes and the glow time control unit I have changed already, that’s why it might not be a relay ? if yes, where is this for the glow candles Thanks in advance