Secondary Air Tank slow to build

[Rawze]

(05-31-2023 )RByrd Wrote:  It’s the same with or without the trailer connected. All the tanks are dry. I’ve aired everything up to 125 psi, turned truck off, key back on and it still had 112 psi 45 minutes later. It’s only slow to build the air for some reason.

you also mentioned it is a 2013 truck ... how old is the compressor?. more than 800,000 miles or more than 15,000 hours?... maybe its worn to the bone and simply time for a new one?... along with a new air dryer unit?.