The gauge of wire is due to the extremely low current requirements of LED's, and has practically nothing to do with much else. Check your connections, check polarity, check that the fuse isn't blown from when you accidentally "jumped something that one time really quickly".
Depending on the method used to splice into the existing wires, that's where wire size for the LED's may come into play, I suppose. Check that you have continuity through the connector.
Depending on the method used to splice into the existing wires, that's where wire size for the LED's may come into play, I suppose. Check that you have continuity through the connector.