16CH relay not working! HELP

Using Arduino Programming Questions
#1

Hi.
i m using this relay module:

i m using the blink sketch just to test it.

when i connect the GND---GND 5V---5V 13---in (no external power supply connected)

the led from the relay blink but does not change the coil position

when i connect GND---GND 5V---5V 13---in and the DC+ and DC- from the external power supply (12V 1.2A)

the arduino just turn off

when i connect GND---GND 13---in and the DC+ and DC- from the external power supply (12V 1.2A)

nothing happen

I have no clue what is happening.
How can i make this work? i have been searching around in the internet and nothing seems to work.

#2

if you want to conmute a relay module, you need to put the digital pin in LOW, instead of the HIGH, in order the coil to change position.

#3