Hey ! Finally got signed up over here..
Ill crawl under my truck and pencil out the dump valve setup. I need to change the rear bags bacause they are weather checked bad, but based on my initial inspection the cup under the bag has a puck thing in there (ill snap some pics when i get mine apart) when the truck comes down it lands on that..
The bags plumb into the load leveling lever gizmo and the 2 lines run up to the front, 1s the main feed to air up. Its has a regulator off the main tank. The other is the dump portion, that makes it way to the dash, ill trace that out for ya at some point.. It seems pretty straight forward and they have a safty thing in there somewere that prevents you from dumping when the truck is running, so no low rideing u-haul truck for me..
89 S1600 ToyToter3000 - 7.3IDI, 5speed Spicer, rear air ride. Jeep toting u-haul RV special