I have an entry way ceiling light that we are replacing. That light is controlled by three other switches and works fine. I removed the old light from the ceiling and installed a new light. The old light had many wires coming out of it, the new light fixture only has two. There are three wires coming out of the ceiling, red, copper and one either white or sprayed white. I hooked up the house copper wire to the loop that the light hangs from. I then hooked up the two brown wires from the ceiling lamp to the red and the other house wire. Pretty straight fwd.

Now, I try the light. Nothing happens, I replace the bulbs, nothing happens. I notice, when I am switching the light on and off, a light OUTSIDE is now turning on and off. All three switches that are supposed to control the entry way light are now turning on and off the light outside! The switch that controls the outside light still functions.

I removed the new light fixture, now, those three switches don't turn on the light outside, and the switch that controls the outside light functions as normal.

What is going on here? I understand how three and four way switches are installed, these switches should have nothing to do with the outside light... The only thing I can think of is the new light has no ground wire, I assume it relies on the metal in the fixture to provide a ground. If the new light fixture is not getting a good ground, would that cause the three switches to fail to operate the correct light and somehow interfer with the outside light?

The original light has a green/yellow wire, two blue wires and a brown wire. If I remember correctly, one of the brown and blue wires were together.

Is there a polarity issue? Grounding issue? I never messed with the switches at all.