I had same problem on my 05 Magnum. From what I recall there is very little you can see or service even with it out. Definitely nothing from under dash. Gotta pull the cluster. There are no bulbs. The whole surface glows (or not). Started as intermittent and got worse till it was off more than on... Changed the switch. No improvement. Changed the cluster. Problem solved. A year later my RPM gauge started going intermittent and died. Never tried to fix that...