Hidden dump valve for 1/2 bath on 32QBBS

I can't figure out why Forest River neglected to label the dump valve for the 1/2 bath black water tank on the 32QBBS. Maybe I forgot or they didn't show me on my walk through but this past weekend I spent the better part of an afternoon thinking I had a clogged line on my sewage tank as the half bath toilet was backing up. As a last resort I started dropping the plastic under carriage cover and finally noticed the dump valve for the second black tank mounted on the frame rail. Needless to say I will be getting a label made for this valve and sticking on the exterior as a reminder. Am I just an idiot or has this happened to anyone else? They really should have mounted this valve in the same location as all the others in my opinion.

Thanks for the heads up, I am suppose to have 3 tanks too. I can only find 2 dump valves, I best get under it and see if there is a third one.
Thanks agian
Bear

I have the 32Qbbs and mine is labeled and has the little access door for all of the valves. I have 4 total. Two grey's and a black in the front and the black in the back for the 1/2 bath. Both ends has the access panels.

I also "discovered" this hidden valve while looking for my fresh water drain. I have a 28RKBS with a galley tank extra. My valve is located at the rear, just past the slide, up on the frame. The PDI guy definitely never showed this one to us.