Problem with start of motor

Hello.

I have problem with start of motor. 2.0 Diesel 120kw

I have no error on OBD and the engine when is cold not start after 15 second full turning of engine (when start come white smoke)

When i connect the voltage +12V direct to glow plugs for 2 seconds engine start immediately.

I have checked:

- Acu - ok (very fast turning the engine)

- glow plugs - ok ( I check them with ohm meter and with 12V on - touch with 12V on each cable and current go

I have questions about my glow regulator ....

I have this regulator:

Vauxhall Astra Insignia Etc 1.3 2.0 Diesel Glow Plug Relay New OE Part 55574293

DESCRIPTIONVAUXHALL ANTARA, ASTRA J, CASCADA, CORSA D, INSIGNIA A, MERIVA B, ZAFIRA CDIESEL GLOW PLUG RELAY CONTROL UNIT FITS ENGINE CODES: Z13DTJ, A13DTC,…

vauxcentre.co.uk

4 poles connector wires go to glow plugs - I checked them, all wires and connector OK

5 poles connector

- center plust 12V OK

- 4 pins around

- Black ground OK

- +12V when I turn key ok

- than i have on two pins around 10,5V ?????

When i check the voltage on my glow plugs i have around 2-3V jumping voltage? It is this normal?

What I can check my glow regulator and it is some wiring or electrical scheme available?

Thank you for help

Best Regards Taubi

P.s. You can write me in Deutsche I understand but it is not easy to write for me in Deutsche.