secondary air injection

I recently had my check engine light come on in my 99' blazer. I went to auto zone and they said that there was a prooblem with the secondary air injection. They also said that this was a problem that they rarely see and are not sure what to do about it. I would like to know what is causing this problem, and what has to be done to fix the problem.

this is a very common problem there are a few chevy bulletins for it. water gets into the air hoses for the air pump and screws it up it also blows the fuse. the fuse is located behind the batery in the fender. try removing the ruber pump hoses and drying them out with compressed air and replacing the fuse that usually fixed the problem but sometimes the pump is damaged and needs to be replaced. good luck with this problem

ours is doing the same thing,3 fuses blown now they think the realay is sticking so they r changing it

Where is the relay for the A.I.R. ????