> Wiring an extra 12volt outlet in the back this evening for my Electric
> cooler.
> 
> Does anyone off hand know the polarity in a 12volt [ lighter] socket?
> 
> I am thinking center pole is positive......
> 

You are correct-- center positive, outer shell ground. Always good to
do a "sanity check" with a voltmeter though, just in case the PO did
something naughty.