Troubleshooting - 12v Relay Module

Troubleshoot Power Connection

Check the 12vdc power supplied to the relay board.

If the red LED is not lit, check that the relay board is getting 12vdc power. Again, make sure the key is turned on.

With a digital multimeter, measure the voltage across VCC (+12vdc) and GRD wires (not the pins). You may need a small piece of wire or a paperclip to insert into the small connectors. Be careful as they are small connectors and delicate gauge wires that can easily be damaged.

Use a pair of small needle nose pliers to remove the small connectors. DO NOT pull on the wire.


  • Is there +12vdc power across the wires?
Yes - If there is +12vdc supplied to the relay module and the PWR LED (red) doesn't illuminate, the board is defective and should be replaced. Replacement 12v relay modules are available in our parts shop.
No - (Abnormal) Click Here