Arduino Controlled relay - heating pad

Dear All,

I am a beginner with Arduino.
In my project I need to connect a 5VDC heating pad to relay and Arduino. I made the following connection.

Arduino Pin 13 - COM of Relay

Arduino Pin 7 - Green wire of Relay power

Arduino GND - -Ve of 30VDC power supply

Relay NO - +Ve of heat pad

Relay COM - Pin 13 Arduino

Heat Pad -Ve - -Ve of power supply

I connected all the GNDs together to -Ve of 30V DC Power supply ( Arduino, Relay and Heat Pad)

But when i check the voltage across the heating pad when the circuit is closed (ON), it only shows 0.488V DC and hence the heating pad does not warm up. If I directly connect 5V and GND to Arduino board, it warms up in minutes.

The same connections made for LED works fine. I understand that LED requires less power and hence it works!!

Could you please tell me where I possibly went wrong?

Thanks in Advance
Medico