When you power on the TIU with the stereo cable plugged in, the red light won't blink at all. If that red light blinks, you need to check your stereo cable.
Thousands of TIU's have been upgraded by Conumer Loader without the frustrating issues you have described. The program does allow you to choose which serial port your TIU is connected to. Look under the OPTIONS menu item and then select Serial Port. If you have a bunch of Bluetooth virtual serial ports it will take the program a while to scan those ports to determine which ones are active.
I don't like using the "Auto" COM Port selection, as I have many virtual Com Ports on my computer and it takes forever to find my TIU. I prefer to select the Com port I know my TIU is connected to. I assume that you are connected to the TIU with a USB cable and it can be tricky to identify exactly with COM Port your computer created to access the TIU. This same information applies when connecting a USB to Serial adapter into your computer for the pre-version L TIU's.
You'll need to go to your device manager and expand Ports (COM & LPT).
Take note of what is listed and then plug in your TIU and see what changes, the new COM port number is the one you want to select in the CONUMER LOADER, from the Options drop down menu serial port setting.
Also remember that MS Windows will track the which USB port you plug your TIU into. If you plug your TIU into a different USB port, Windows will create a new COM Port to access it.
