Sounds like you are having the same problems I have had. I would say if you have an old fashion azalea, move it to the east side or north. Also, I sprayed mine with ferti-lome systemic fungicide which seems to have gotten rid of the yellow leaves. I have fertilized a lot with miracle grow.

If it's dead to within 3" of the ground, I'd call it dead, remove and replace it.

And, the only problem fertilizer can solve is low fertility which is rarely the case with azaleas - they have somewhat low nutritional requirements and when grown in soils with the right PH (acidic) will often never need fertilizer.