[Fulltiming]

The ride height valve itself has no electrical connections. It is purely a mechanical device that uses a rod connected to the axle to move a lever that rotates a valve either allowing more in, letting air out or stopping all air from entering or exiting the airbag(s).

When the front leveling rod (in the middle of the coach side to side and above the front axle) is loosened, raising or lowering the rod with the system in travel mode should cause the front end to raise or lower. If it does both then it is just an adjustment issue. If it doesn't then the valve is bad.

The only way that electricity, with the potential of a bad ground involved, could be involved would be if the solenoid that controls the shifting between travel mode and level mode is not working properly.

I would concentrate on the front one first and see if fixing it solves that rear issue as Dean as suggested. Since you don't have a tag axle, I think that the potential is limited but in any case, I would focus on the front first. When adjusted properly, the metal tube near the bottom of the sidewall just behind the front wheel should sit about 11" to 11-1/2" above the ground.