Air Conditioning - Outside unit always runs unless I kill the power

I came home from vacation and found the outside portion of my airconditioner running. It was a huge block of ice. The inside blower was not running because the temerature in the house was lower then the thermostat was set. The airconditioner should not have been on.

The inside part was also very cold. There was a small block of ice around the refrigerant tube as it entered the inside part.

Setting the thermostat to off or heat would not stop the outside fan. I had to pull the breaker outside.

The gas heat portion of the system seems to still work fine.

Since we are now in the heating part of the season I have a few months to try and fix this my self.

The unit is a 2 ton bryant with gas heat. It is about 7 years old.

I have looked some and I am guessing that the contactor has gone bad. How easy is that to replace?

Any help would be appreciated!

Just turn power off to the outside unit. you will see the contactor there where the big power wires go get the ## take it with you and get one just like it. Mark down how the wires are on it for high V and 24 V. Points burnt, bugs get into them can all cause it.

ED ;)

ed is right, very common