Defrost Air Distribution Flap Issue

Yeah, had something similar with my Insignia. Check the air circulation and ventilation system; the blower motor might be the culprit. Have you noticed any windshield fogging or strange sounds coming from behind the dash?

Windshield fogging is definitely present, and I suspected that the blower motor might be related. Do you recall what the eventual repair cost was in your case, or any additional symptoms you have experienced?

I remember paying around 95€ to get it sorted. The low heating output and the fogging are classic symptoms. It could be a dodgy connection as you suspect, but honestly, you're best off getting it hooked up to diagnostics at a decent workshop. Saves a lot of headache.

Thanks for the advice. I'll get it checked out professionally as suggested. The symptoms you shared confirm my suspicion.