STC-1000 Help

Built my STC-1000 around 6 months ago, sometimes it seems to work flawlessly while other times it works the opposite of what it should be doing. I have checked my wiring 3 times minimum and I'm 100% it is correct. So the problem I am experiencing is:
When it is either supposed to be turning on just the heat socket or just the cold socket it is turning on both the heater and the freezer.
So I know that the computer chip is functioning properly and the problem is in my socket.
Unfortunately the old house I live in has mostly groundless sockets so the grounded power cord for the STC unit is being plugged in through an adapter with no actual ground.

Could this lack of a ground be causing the circuit to overload over both sockets or is there a different issue in my circuit.
If it is just the ground I can replace the socket with a grounded one and problem solved.

Just wanted to check anyone's prior knowledge before I started troubleshooting.

Thanks for any help and electrical advice!!!

It's not the lack of a ground. Did you break off the tab on the outlet?

Edit:

Perfect!!! Such a quick fix... Working perfectly now. Thanks for the quick tip.

If any others are reading this thread with similar problems it is important to note that you should only break the lead on the positive side of the outlet; otherwise you completely break the circuit and will have no power!

#dumb dumb dumb dumb dumb