153ir how do you test?

I guess I would start with an ohm meter. Apply power to the unit. Touch the probes to the common input and the Normally Open contact, then try to activate it by motion in front of the sensor. If the ohms go to zero(ish), then it works. If not, that's not good.

This will test both the sensor circuit and the relay that it drives. The only problem with this method is you won't know which part of the device is bad.

If you tested as shown in photo then I would expect constant power on the 2 terminals (Com-NO).  That is because you have sensitivity cranked and something is right in front of the 153IR.  Basically the device sees a train in front and is closing the normally open (NO) contact. 

You then connected to the NO-NC terminals and that will never close in.  

Hook it back up as you have pictured.  Turn sensitivity down to middle.  Put something in front and verify power/circuit completion.  Then remove object and allow for time delay to expire and confirm no power/circuit interruption.

Thanks.  I’ll give it another shot.  If I turned off the lights would I see something in the red eye?   No idea they are that sensitive.  

"someone said" (here on OGR) that a digital camera will see the IR.  Hmmm, I wonder if an iPhone will?  Anyway I haven't verified either, but it might be worth seeing if you can 'see' the IR LED - which is certainly one of the things you'd want to test...

You can start chasing the IR but only after it fails the functional test.  The goal here is to determine if the 153IR is functional.  Your eye alone cannot detect the infrared.