Peterbilt SmartAir system

Good to know.
It looks like this (on the left side of the battery box). Maybe it will help you one day when you will see the same customisation)

 

AHH- I see now. Your first photo of the relay is upside down from the bottom.

Didn't recognize the photo.

 

Does anyone know if the SmartAir should run off of shore power without draining the batteries? I believe my batts are bad and need replacement. I’ve tried running it with shore power and it still drains them fast and then then take for ever to recharge.

 

No the system does not run directly off shore power. The system operates exclusively on 12vdc.

 

Yep, the ac runs off the batteries and shore service runs the charger. So bad batteries or corroded connections would cause issues keeping up.