2003 transit cold start problems

[gerb1969]

2003 transit .When temperature outside is freezing or below zero van cranks for a short time and stops. Can sometimes do this 10 times before it starts. I have replaced injectors, glow plugs, starter motor, checked battery, new timing chain. It seems like something electrical is stopping the van cranking for a long time. This only happens in cold weather - it starts first time when warm or temperature is above freezing.
Any help much appreciated.
Thanks

[knobby1]

Ignition switch maybe..??

Lord Knobrot