correct wiring 12 volt polarity

[Mike and Sherrie in VA]

I would connect an ohm meter to the refrigerator frame and test both wires. The wire that's connected to the frame would be my negative.

As far as testing the current configuration, I think bross summed it up pretty well.  See the above quote...  The wire connected to the frame should read 0 (or very close to 0) ohms, whereas the positive wire would read probably an open circuit (or almost inifinite resistance, as if you had not connected the meter at all).

 

[1275gtsport]

Just to update for anybody that was watching this thread. I reverse engineered the 12 system on the fridge itself. I found a reference to testing the electrical coils themselves and the fellow explained how to "hot wire" the coils (he was checking to see if the control board was dead) so on my fridge nothing is grounded to the frame of the fridge. but by finding the ground and power wires leading to the 12 volt coil I was able to determine which unmarked white wire was power and which was ground. good thing because I would have wired it wrong! the ohm meter never lies! you just have to measure the right thing!

Thanks for all the help.