One thing to also be aware of if Hector's suggestions do not correct the problem. The ride height valves have an arm that pivots up or down when driving to maintain the coach's relationship to the road. The arm is free to rotate about its pivot point and at some number of degrees of rotation, either up or down it passes the point at which is will function. When it does the air flow into of from the air bags is blocked. If you manually place the coach in the approximate driving position using the leveling system, if the balance of your coach's leveling system is functioning properly it should be OK. If your entire coach will not rise or lower to the driving position it is unlikley all 3 ride height valves are not functioning simultaneously so if that is not the case don't waste time thinking it is because the odds of all three doing that are slim.

Having said that however, the fact you have an indicator light showing the leveling control is still "on" suggests to me the problem is associated with the electrical switching side of the system and not the pneumatic side. Make sure the switch which controls the suspension is in the position it should be for driving (every converter uses different terminology and I don't know what CC uses to describe the switch position for travel) and start there to confirm you are getting power to the solenoid valve that controls the driving position. I think your vintage coach has a 4 solenoid manifold located on the rear bulkhead in the steer compartment. I think the second solenoid valve down should be the one that must be energized to keep the bus in the driving position.

If you cannot sort out why the problem exists but need to drive, disconnect the electrical connections to all but the #2 solenoid valve and find a source of 24 volt power (I think it is 24 volts) to energize that #2 coil and your coach should go to ride height or the driving position. The other solenoids are for leveling the coach and are not energized while driving.

Welcome to the asylum. Remember, we always answer questions here. Just don't expect to get correct answers. When they are correct it is pure luck.