Is the Wifi module working?

[pfeerick]

Thanks for the additional information.
The system confirms that I have the latest version of wireless-tools installed.
The config commands return connection information only when I have
an USB wireless adapter or an Ethernet cable attached. When both are
off I get no results; obviously the built-in Wifi module cannot be found.

Would you like to see screen photos of the various replies?

Ok, a quick clarification then - when on the debian mate image, why can't you use the network manager applet icon up on the top right (it probably has two green dots and a spinny thing if the ethernet isn't plugged in)? Your wifi module is plugged in the right way around (the antenna connector is on the inside edge), so using the debian mate image there is no reason it shouldn't just work unless you have a faulty module. Has the module ever worked?

My apologies, the check of the /etc/network/interfaces file was really only relevant if you were using the minimal (non-GUI) debian version, so there's no point fiddling in that. Since you're using the GUI, it should just work - when you click the network manager applet icon in on the top right, it should the list of available networks and you then click on the network name to enter your password, etc. And if you need more options, there is an 'edit connections' entry that lets you do that.