Propane tank as air tank

[Twoxentrix]

My relay went out along with the air sensor to the tank after going through high water, that's why I inquired about high water first.
Once I got the compressor to work again, I also had the issue where rear lockers would work but not the front ...turned out to be some sort of solenoid that also went bad - It controlled the air released to the front lockers when I flip the rocker switch for the front lockers. Fortunately I could still use the front since mine still have the manual locking hubs on them as well.
Follow the air lines from the front lockers to locate that solenoid.

EDIT: When you locate the solenoid have someone flip the rocker switches for you - While you are under the van you should be able to hear a faint "click" as they are engaged.