By switching network interfaces you have switched DHCP leases, which in your case might have lead to a different (or missing) DNS name. 

Alternatively, the Pi might be blocked from accessing the WiFi due to a missing or wrong encryption key (double check!). 

I recommend using the `nmap` tool (from [https://nmap.org][1]). 
It's a universal networking tool for a multitude of purposes that belongs into every tinkerer's toolbox. 

Assuming your Pi is configured for your WiFi and receives an IPv4 address in the range 192.168.1.x, the canonical way of probing a local network for running hosts is:

`sudo nmap -sn 192.168.1.0/24`

Substitute the actual address prefix according to your local setup, but keep the trailing zero befor the forward-slash. 

You'll end up with a list of all host names and IPv4 addresses within your local network. Pick the RasPi's IPv4 from the vendor name. 

The parameters `-sn` perform a special kind of probing that looks for running hosts and tries to find their names. 
See `man nmap` (or the online documentation) for a list of parameters and their meanings. 


  [1]: https://nmap.org