12VDC is a + (plus or positive) and a - (Minus or negative) - Neutral usually refers to 110V or AC voltage -
Two Stupid question to ask here but always good to ask the obvious first and please dont take it the wrong way cause I am not calling you stupid - most people get offended and thats not
what I am trying to do
1 - did you check the Bulbs?
2 - Did you pull the light out and test it with the battery to make sure the light is good first or run a wire from the negative or ground side of the battery to make sure the light worked since you say it has 12 volts?
Here is something I have used to figure out other electrical issue when chasing a wire -
Make sure the power is disconnected or you will blow a fuse
I have a device called a Fox and a Hound or known as a cable toner (has many diffrent names for it)
tone the wire out to see if you can locate the wire - I have found many wires this way and makes it easier to somewhat locate the wire - you can get a toner at Home Depot and they range from $50 on up
hope that helps