Yes that was the first thing I tried.I assume you’ve replaced the bulb, right? They can and do go dim before they break the element inside of them.
Thanks I’ll give that a tryMaybe pop the fixture out and run a loose wire to it from the battery and apply 12volts directly too it to see if it’s brighter. Could be a bad ground as well. If the direct 12 volts supply fixes it then that’s your clue. If not, run a jumper ground to see if that makes it bright.
Au, then there is a real problem, they need very few power.I did that too I barely illuminates. Very dim as well.