Ignition lock is OK, becouse there is power supply on instruments, VECU and other systems. Ignition lock actuate 3 relays: K1 - 15R (radio), K2 - kl15 - ignition, K3 - Body builder relay. K4 - starter enable ralay. actuated with VECU on some models, generally with Volvo D12D/D13 engine.
If you can pull the codes, I'd call a Volvo shop with them...You can post them here but I'd call a shop first...My truck(also a 2005 Volvo) was recently in Volvo shop and heard the SA do a little diagnosing over the phone, but he had to have the codes...Have the specs for your truck handy also...Good luck! P.S. Having the headlights go out can be pretty scary in some places...
I have full code list to help drivers over the phone, becouse company I work for owns 500 trucks, Vovlo and Mercedes
The light module shows this code: mid216 pcid10 fmi5 Which is referring to the brake lights, but they are fully functional.
Is is just the left taillight. May be the bulb of wrong rating is used ore LED. If you use leds dealer can reprogram LCM for LED disabling bulb failure monitoring for taillamps Can you read engine codes?
