OP,
The best thing would be to go read the air-ride system in the Service Manual which you can find in pdf form on this forum (free)
HERE. It's probably the most comprehensive how-to-fix for your air-ride system out there. Read through it quick the first time, don't worry if you don't absorb everything, or if it seems confusing. Then go outside & look your air-ride system over so you can put context to parts, from what you read. Then come back a couple days later and re-read the whole air-ride section for detail. You'll be armed with knowledge and suddenly the murky will become clear as gin. You'll know where to start and probably zero in on the root issue quickly. You'll probably know more than many Ram mechanics on the system. And, you'll be armed to quickly resolve whatever issues could potentially come up in the future. Knowledge is key.
It's an entire 'system' with a lot of relatively simple components. Hard truth; there's really no way to effectively scatter-gun out ideas via a forum that'll point you to the problem. Could be a bunch of things ...all small. The hours you waste asking others what the problem is (could be a dozen potential things), or days/weeks sitting at the dealer ...you could just fix it yourself..and most times it'll be something small. Although the dealers usually toss out: "You need a new pump/valve assembly!" But most problems are usually small things. There's a systematic approach to troubleshooting it.
Best of luck