More apparent when cars been ran for a period, amber exclamation comes up in centre of dash and toggles between that and error message ' parking bulb failure' in message centre on left of dash (04 s80 d5 manual) . checked a million times to ensure all bulbs on and always are even during the times the message is popping up. is it just a case of cleaning every bulbs connection for corrosion? tia

 

it could be that you have a wrong size bulb, a dirty connection or the socket itself doesn't seat the bulb cleanly or you have a bad ground point that may need to be cleaned.

 

Based on my previous experience (with different Volvo), you need replace socket bulb ...In past, I got problem mostly on cold days and I feel your pain ..It is very annoying have message pop in here and there ...You can try clean connections as first step but in my case problem returned after couple of months.