DSC Wifi not working

The WiFi unit must be set to MTH mode and all connections disconnected except power and the USB to the computer for LuCi interaction. Version 1.1 is the latest update.  

Hi Gerald - the Wifi switch is in MTH mode, only the power and USB are connected.  The unit is not transmitting  the MTH network wifi ID.   

I stated incorrectly. Disconnect the USB and try LuCi  

My conclusion thus far is the Wifi unit has failed.  It's unresponsive expect the power light and lan light illuminate steady.  The purple TIU connect light flashes briefly once and extinguishes at start up.  The reset is unresponsive.  There is no transmitted wifi ID in either MTH or HOME mode. The unit and my PC are on the same network.

@shorling posted:

My conclusion thus far is the Wifi unit has failed.  It's unresponsive expect the power light and lan light illuminate steady.  The purple TIU connect light flashes briefly once and extinguishes at start up.  The reset is unresponsive.  There is no transmitted wifi ID in either MTH or HOME mode. The unit and my PC are on the same network.

Which is likely correct- the firmware can get corrupted and thus the network interfaces never start- so externally via networking alone- you cannot troubleshoot because you cannot reach the interface because networking is not working.

I've got a few of these bricked modules, that one day when I have extra time- yeah right- I might try more invasive serial connection to the module and then probably have to jump through hoops to reflash across the serial data lines of the module.

Also, since MTH built the last batch of these, one could hope that MTH parts and sales got some parts- but that's not the case?

I'm a little late to the party here, but I have a few things to try from my experience.

RESET. Power up the WIU and wait 90 seconds for the device to complete the boot process. Use a paper clip and insert it into the RESET hole to push & hold the RESET button for 10 seconds (you should feel the click) and release. Wait another 90 seconds and then unplug the WIU. Plug it back in to see if this resolves your issues, especially with the device not broadcasting a WIFI network.

Wifi is not the only way to connect to the LuCi interface.  You can also use an ethernet cable to connect the WIU to your home internet router. This process will take a bit more tech skill as you need to know the IP address your home internet router assigns to your WIU. You can then access the LuCi interface. In most cases, I find that the WIU configured itself with the wireless radio turned off or hides the wireless network so that the name of the network is not visible to any device looking for it.

In situations where the TIU light does not light up, I reload the firmware into the WIU using LuCi. This alone has fixed several WIUs with this symptom for me.

A video of the boot-up process of your troubled WIU is helpful. How the lights flash and in what sequence can provide some good troubleshooting information.
For reference, this is a video of how a TIU boots up normally:

Since I cannot communicate with my MTH Wifi unit; it's appears damaged beyond reasonable efforts or bricked as Vernon suspects.

I have 4 TIU's running 6.0 and 3 working Wifi units.  I could buy another wifi unit.  Or I'm thinking I could preorder the new MTH TIU with wifi., 50-1039.  I presume this is the long await TIU upgrade.  I realize it doesn't support wireless remote but I could tether.   My question is compatibility with my existing TIUs ?  Is it expected to be seamless  or are there negative functionality impacts ?