Here is a rear suspension air system diagram that Richard Entrekin & I put together so we could understand the air flow in the rear suspension. This schematic applies to coaches that have one rear six pack and covers years from the 90s into the 2000s. An important fact that is not clear in the schematic is that the tag axle air tank is actually two tanks that are separated on the inside. We hope this will help others troubleshoot their systems.
We have a question whether the travel mode utilizes the mercury pod also for leveling? After dumping the air I saw that the front and the passenger side yellow lights were on indicating they needed to go up to travel but there was no yellow light on the driver side. Are the yellow lights due to the mercury pod adjustment?