I know that there are plenty of questions related to relays, but I have to ask. I am trying to sort out the issue and spend hours reading but cannot make progress. 

I have [SainSmart 2-Channel 12V Relay Module](http://www.sainsmart.com/arduino/arduino-components/omron-12v-2-channel-relay-opto-couple-for-arduino-uno-r3-raspberry-pi-arm.html) for Arduino and wired it according to picture. 

[![SainSmart 2-channel relay](https://i.stack.imgur.com/xzwDc.jpg)](https://i.stack.imgur.com/xzwDc.jpg)

Arduino UNO R3 board is powered from 12V plug external power supply. I take that 12V to power JD-VCC on relay (from VIN). Arduino 5V is used to power optocoupler circuitry.

I want to use to power 12/24/220V devices (on picture I wired 6V battery for troubleshooting). 

So, when I set PIN7 to LOW i would expect that fan spins up. LED on relay goes RED, so I expect it is sign that relay is activated. However, fan does not power on. 
When I bring PIN7 to HIGH, I hear click; LED goes OFF. I assume it deactivated relay. All the time I have 6V on voltmeter. 

What I am doing wrong?
I really tried to find answer around, but either I do not see or it is not so obvious. 

Thank you, 

[![WIRING](https://i.stack.imgur.com/XUBE7.png)](https://i.stack.imgur.com/XUBE7.png)