The "TANKS" switch is not getting power to it. After looking threw the wiring schematics I'm unable to determine the power source or location of its electric cut over valve?, breaker?, Fuse? any direction is appreciated.
If you mean the "Air Tank" switch near the driver's left elbow (assuming this is a 2003 or newer), that switch was added in 2003 simply as a convenience and shouldn't be used that often (as in - rarely). It's there so you can use the aux compressor to air up the main tanks without running the coach engine simply as a courtesy to your fellow campers to be less noisy when you're getting ready to depart.
The aux compressor isn't sized for doing this on a regular basis, nor does it have an adequate air dryer to do so.
BTW, it's a good idea to add your coach year/model to your forum profile signature. That way your coach information shows up in every post you make so folks don't have to ask. There are enough differences between years that the answers depend on that info :)
Thanks Michelle, I had no idea what a tanks switch was.
yea copy that "should rarely be used " I use it maybe 2-3 times a year. now that the system does not function I'm trying to sort why?
which takes me back to the posted question.
I'm trying to dig that up for you - that switch operates a solenoid valve that I *think* is near the aux compressor. There's also a check valve in that line. We worked on ours 12 years ago, and I'm trying to find more than just a post that says we did that - something with photos.
Still digging - this might help
Air Tank Switch (https://www.foreforums.com/index.php?topic=32156.msg286692#msg286692)
in particular this post in that topic - you may not have the "accurate" air schematic - Air Tank Switch (https://www.foreforums.com/index.php?topic=32156.msg286822#msg286822)
Schematic showing solenoid valve, I'm now checking 12V schematics for location of power source https://www.foreforums.com/index.php?action=media;sa=item;in=3302#viewitem