Putting in an after market cigarette lighter, but I don't know which of the two wires (looks like yellow with light green stripe or light blue stripe, and a black wire) is positive and which is negative. I plan on running an inverter through it, so I don't want to get the polarity of the wires backwards-- I think that's how I fried my last inverter.
Should be a simple question, but google search results are just way too vague.

 

Solid Black wire will be a Ground in any Ford, Black with a colored stripe can be 12v

If you are doing any wiring you should have a Volt Meter or at least a 12volt test light, they are not expensive and way less expensive than a fried new device if its wired wrong

The main problem with wire colors is that you NEVER know what changes a previous owner may have made, if its a 2020 vehicle then you can be "pretty sure" factory wires haven't been changed, pretty sure, not for sure
At 32 years old(1988 Ranger) its a roll of the dice as to any changes made in the wiring

 

thanks
I think its original wiring.

 

"I think its..............." has got me into more trouble that I would care to admit, lol, and not just with vehicle wiring