Q: 2005 Chevy Avalanche dash lights occasionally go dim.

Yes, but any component in the lighting circuit could cause or contribute to the problem. An intermittent fault is causing a voltage drop in the circuit and that, in turn is causing the lights to dim. Often, there is a common ground in the circuit and that ground is loose or has a high resistance. Unless the problem turns out to be in a visible accessible segment of the wiring, to identify the segment of the circuit that has the fault will require circuit tracing and that usually requires that you have in hand the factory wiring diagram. To get this resolved expeditiously, the best thing to do is have a certified Mechanic, dispatched by YourMechanic right to your location, perform an electrical circuit/component diagnostic. In the course of that, the mechanic will pinpoint the fault and get it repaired. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.