how does this hurt my truck if i don't fix it?
can i "pull a fuse" to put out the obd light?
will truck run with check valve off?
how do i check blower, hook to 12v?

Problem is either a bad check valve/solenoid or a bad AIR pump, it will not affect the operation, but there is no way to stop the CEL. It will fail an emissions test if your state has one.