I bought an HKS DLI II off a member on here and I noticed (when the car is turned on) that the little red light is not on? Is it supposed to be or does this mean it is not working?

 

check the ground wire. the red light should be on

 

It's supposed to be on. It could be as easy as the light being burnt out bc people tend to mount them in locations that are exposed to extreme vibrations. (psgr side motor mount) I'm sure there's a way to probe the wire harness to check for voltage output...but that, I don't know which wire is the exact one.