My Whirlpool Refrigerator stopped working. is it out of coolent???

It is a side by side frost free numbers Make ED25RFXFX03
S/N SL0445884
Came home the other day to find that the freezer side had stopped working, after I moved everything out. I left a temp probe in there to see how low it got, 38 then a day later the Refrigerator side stopped working. I pulled out the frige and took off the bottom found the fan and a black canaster with R134a on it. I guessed that was the gas but was looking at it and I can't see a way to recharge it myself. I found something on the side that was white with 2 wires out of it, but the plug and that side of the tank appears to have soot on it.
So is it the gas or did that thing on the side of the tank short out.

George Gandalf_79@comcast.net
February 2006