Brake Lights keep staying on

I have 1989 Oldsmobile Cutlass Supreme Coupe.
I had a problem with the brake lights not coming on, so I replaced the turn signal switch and everything started to work correctly.

After a while (month or so), the cruise control stopped working suddenly, and I noticed that when I turn the car off, the brake lights stay on, no matter what.
I took the hand brake off, there is only one wire and I am guessing that for the indicator on the dashboard.
I also looked at the brake pedal, and when the pedal is not pressed, the switch goes all the way in. I even tried pushing the switch all the way in by hand and ask a friend to see if the brake lights turn off. They don't.
According to the manual, its a total pain to take the brake switch off, and I don't really want to do it unless I know thats where the problem is. I know the turn signal isn't the problem, because its brand new and I didn't have this problem when I installed it.
Brake lights including the small middle light mounted inside the car keep staying on, so the only way I figured out to turn them off is to unplug the battery. The turn signals work and the emergency lights work as well.

Any help would be appreciated.

After a couple of days of stuggle, I figured it out.

I was able to take the brake switch out, but that was the biggest pain in the ass. There are 2 connector that you need to unplug, but there is so little room and no way to see, you basically have to do everything by touch.
After a few cursed words, I got one of the connectors unpluged, but the small one is pretty much impossible to unplug without pulling the switch out. The key was to slide the steering shaft colar as far as physically possible.After pulling the switch, I basically figured out that the switch is the problem. The lever that moves with the pedal wasn't pulling the contacts with it in order to turn on/off the brake lights. There is a small nob inside the casing of the switch that basically holds the lever attached to the contacts, but the lever can easily hop over the little nob and functionally leave the contacts where they were last. In my case the lights were on. All I had to do was move the lever over the nob and the switch works fine now. Installing is almost as hard as pulling it out.

My problem could have been fixed without pulling the switch, although there was no way for me to know that at the time. If you take the lever off of the pedal and move it all the way back and apply a good amount of force, it will snap over the nob and should pull the contacts with it.

Hope this helps someone.