I have a cs-8030 that will not recognize the size of paper in tray 3.If I pull out all paper out of tray,it will say to load paper in tray 3.Paper tray does go up,but will not recognize paper size. All other trays work fine.Tried swapping trays3/4 around, but same problem.

Look behind the tray, there might be some paper wadded in there. This can throw the sensors off.

copier in shop checked for paper behind tray,none

The connector at the rear frame that the paper drawer connects to in turn has a connector that plugs into it from behind. Double check that it is connected. Go ahead and reseat the connectors on the engine PWB while you are back there.

That fails, try swapping the drawer connectors between 3 and 4 and see if the problem transfers. After that go to your wiring diagram in the service manual, you will see that there is a circuit board between the drawer 3 and 4 connectors and the engine PWB. (Drawer 1 and 2 go through a different board if you check further). It's possible that reseating connectors on that board will fix, or else escalate to replacing that board. That all fails, go to the engine PWB.

Point being, you should know to go to that wiring diagram yourself and look to see what is between that drawer and the brains of the copier and start checking every connector and everything that is in-between.

thanks for your help.broken wire at yc5 at cspwb