My check engine light came on a while back with the p0410 code. I just replaced the air pump and noticed that there is a hose that I can't seem to find out where it connects. It originates just above the pump next to another smaller hose that connects to a larger one that runs to the pump. If anyone could help me out and give me some insight into where this hose goes or if it's just there it would be greatly appreciated. I have a 2000 blazer zR2. I'll try and post a picture of it soon.

 

the 4x4 vacuum thread. - S-10 Forum