2 compressors

i read up on how to hook this up..but why does it say to use a starter solenoid?can you not just run 2 relays?

what would happen if i did just 2 relays?

The starter solenoids are just like a relay. Just bigger. They will take alot more amps for alot longer time. It is standard for us to use them on our systems.

i usually run 2 relays per comp.
last truck i had, had 2 viair 450s and 4 relays with no problem at all