check the fuses in the overvoltage relay, on some models a fuse can be burned causing the light not to illuminate, the fastest way to check this is by briefly pushing the button on the 16 pin connector near the battery, if the little red led comes on, then the fuse at the relay may not be your problem, in order to check the actual bulb the instrument cluster will need to be removed, that is pretty easy if you have the cluster removal hooks