Starting issue. 2012 Tiguan

[Transporter]

You have answered your own question about what to do then Havent you.

Always has been wait for the glowplug light to go out before hitting the button. Even on my 1963 Farmall tractor.

The older diesels were more dependent on the glow plugs than a new CR diesels, and can start very fast in summer. But when the temperature gets closer to 0 deg. C, it's better to wait for the glow plugs light to go off.

Any diesel from 1963 would struggle to start without the glow plugs working 100% at any temperature and would not start at sub zero without them.