cluster not working in the dash after battery change,

This is a common situation on these 03-06 GM trucks unfortunately. First off you have two problems - battery drain and dead gauge cluster. The good news, sort of, is that both problems are due to the gauge cluster so fixing it will fix the drain and the dead gauges. The gauge clusters on these trucks are very bad about getting "hung up" so to speak. Meaning when you remove your key the gauge cluster doesn't fully go to sleep but continues to pull a small of current from the battery until it dies, usually in 1 or 2 days. This can be fixed and requires the gauge cluster to be opened up and repaired by someone who knows what to look for and how to test it. The dead gauge cluster situation is also common and goes hand in hand with the battery drain meaning the cause of one is often the cause of the other. Also repairable by an experienced technician. If you'd like to learn more about the problem and how to get it fixed please visit our site at www.drspeedometer.com Thanks Fred Dr.Speedometer