glow plug mark not lit

407 1.6 hdi, the glow plug sign does not light up on the dashboard when the vehicle is started for the first time, I said it caught my attention in the evening. he goes out. There is no problem in the work of the vehicle, takes it in one starter. what could be the problem?

Normally it burns when diesel needs heating, but it should burn at -4 degrees, my old car was starting to burn when it was below 2 degrees.

How many degrees should it normally burn? I have never seen it burn in the 2009 model 308. Besides, we see -3 degrees very easily in the morning?

Valla 206 does not light up, I do not even know if there is such a light. When I open the first contact, I wait and run until the storage airbag lamp is all over.

I have never seen such a light shining in summer or winter for all these years, I don't know what it looks like

Hello, I have 407 1.6 HDI Ex for 5 years. I use it, I saw that light turn on once -17 degrees. But there is the company vehicle Fiat Fiorino, which I constantly use, burning at 1.3 Mjet +5 degrees for 1-2 seconds.