Mkr relay Proto Shield is not switching


i think i encounter some troubles with my arduino mkr relay proto shield. I am wondering if it's working as desired. Let me explain. I try to switch on and off the relay 1 or 2 with a simple code. Informations are coming from my nano every to the Mkr relay. I test voltage and i can see it dancing from 0 to 5 as requested in the code. test 1 : between the vin and the ground = correct test 2 = between ground and vcc = none but between vin and vcc = correct, bouncing from 0 to 5 and back. VCC should be positive, isn't it ? test 3 : between ground and pin 1 or 2 that controls the relay 1 or 2 = none but between vin and pin 1 or 2, voltage from 0 to 5. I also tested the pin on the back of the board of the relay, and it's correct.

But at the output of the NO,NOC & COM connections nothing changes, nothing comes from pin 1 or 2. So tell me if : 1/ the nano every can control the mkr relay proto shield (i also tried with an arduino uno board and it's the same) 2/if the vcc output should + or - 3/if it's possible noting is connected from pin 1 or 2 to the NO NC COM connections. 4/something else is wrong.

thanks a lot for your help.

Take a photo showing how things are connected.

The MKR relay shield is designed to run from 3.3 v. Are you giving it 3.3 v or 5 v?

By default the relay NO, NC and COM terminals are isolated from the rest of the board.