Automatic recognition multi purpose tray

[UredskiDOTcom]

I would like to know is it possible for the LaserJet Pro 501dn to automatic recognise when paper is inserted into multi purpose tray and to pull the paper from it and not from the tray?

[Valsimot]

Plain A4 paper? Set the paper source to automatic, and the printer will print from multipurpose tray if there is a paper loaded, if no paper the printer will print from lower paper tray.

[UredskiDOTcom]

Yes, this should be working like that but its not... When I set to automatic, it draws from the bottom tray even when the paper is loaded on to MPT, for printer to draw it from the multi purpous tray, I need to open the bottom one,,, fruther more, if I set to draw it from the MPT prior, then from the bottom one is not pullig until pressed OK button on the printer... 

[Valsimot]

When both trays are loaded does it print from MP tray when you print something from the printer's menu, not from a computer?

[UredskiDOTcom]

When both trays are loaded  and Demo page is put on print from the printer itself, it still pulls from the bottom tray, 
lets propose that there should be "open door" sensor for the MPT and: When doors are open, pull the paper from the MPT, if not, pull from bottom tray.

[Valsimot]

You didn't setup it correctly, paper source, paper type and paper size.

[UredskiDOTcom]

Automatic, A4, Plaine paper