The Volvo had and still has the bulb failure light on the instrument cluster, on the newer cars with the DIM (Drivers Information Module) it even tells you what the bulb is if you know what Volvo calls the bulb. All of the problems with the turn signal bulbs was not that they burned out but they were blinking too fast. The less than snug fitting on the bulb and socket caused arking and increased resistance in the turn signal circuit so the bulb blinked double time, but it wasn't burned out. When the headlight bulb burned out the bulb failure warning came on.