this should be a sticky. I guarantee I have seen this same question 50 times. There is a search feature here that would have found the answer to this.just so ya know.
But though more rare, it can also be worn "run position" contact in the ignition switch itself.
But ya gotta chk the easy stuff first.
Test all the balast resistors connections for power with a test light.
All contacts should have power them or it's toast.