Vectra preheating lamp error

Sounds familiar! I've got a Vectra too, and had almost the exact same thing happen. Did you notice any rough idling or engine misfires along with the light staying on?

Rough idling, yeah, a bit shaky at startup now that you mention it. Was it definitely the glow plugs in your case then?

Yep, glow plugs were the culprit. After checking them, I went to the workshop and the problem was solved after replacing them. Are you planning to replace them yourself, or let a professional do the work?

Cheers for the confirmation. Thought so, but wanted a second opinion. It ended up costing 440€ to get sorted at the workshop, but at least it's running smooth again!