Funky acting dash brake light

I have a 99' Toyota Camry that has just turned over 150,000 miles.
Two winters ago I noticed that the orange brake light on the dash would come on and stay on. But when the weather became warm again in the spring the dash light went off and stays off during warm weather, and then comes back on again when weather gets cold.

When the light initially came on the brakes worked fine and the pedal was nice and high and firm. I pulled the wheels and found the pads and shoes still had well over 70% of pad and shoe material remaining and the brake fluid is clean and full.

And even to this day the brakes work beautifully except for the dash brake light coming on when cold and going off when warm.
Any Ideas what may be causing this to happen?

One othe side note....I have NEVER used the emergency hand brake lever between the seats since I have owned the car. I have always been leary of using these hand brakes since I have had cars in the past that the brakes would sieze in place and would not release when the lever was released. As a result, I never touch it. And I have never place my car in a situation where I would even need to use it.

Check your charging system. Autozone, O'Reily would do it for free.

Your hand brake might be stuck in it's sleeve by now. Do use your hand brake. It save your transmission.

Good luck,
Sam

Check your charging system. Autozone, O'Reily would do it for free.

Your hand brake might be stuck in it's sleeve by now. Do use your hand brake. It save your transmission.

Good luck,
Sam

Thanks Sam for your reply.

Do I dare mess with the hand brake now if there is a possibility it could be stuck in its sleeve? If it is stuck in its sleeve, and I apply the hand brake, could it possibly remain stuck in the set position with the brakes applied to the wheels even after releasing the lever?
Everywhere I park is on level ground and never felt the need use it.
Other than this light, the electrical system has shown no signs of problems. The battery seems strong and the engine has never had any starting issues, even in the coldest or hottest weather. Wouldn't a faulty charging system result in a weakened battery and starting problems?

Check your master cylinder fluid level. A level below a certain point will trigger the brake light. Cold weather may cause the level to drop below the sensor if it has barely enough to keep the light off when the weather is hot.

Thanks Sam for your reply.

Do I dare mess with the hand brake now if there is a possibility it could be stuck in its sleeve? If it is stuck in its sleeve, and I apply the hand brake, could it possibly remain stuck in the set position with the brakes applied to the wheels even after releasing the lever?
Everywhere I park is on level ground and never felt the need use it.
Other than this light, the electrical system has shown no signs of problems. The battery seems strong and the engine has never had any starting issues, even in the coldest or hottest weather. Wouldn't a faulty charging system result in a weakened battery and starting problems?
I cannot guaranty that your brake will get stuck by now... and who can?

Like Brian mentioned in his post # 4, check the brake fluid level. It is that simple.

Good luck,
Sam

Thanks guys for your help. I will check these things out.
Regarding the hand brake....I think I will not take a chance on it and just leave it alone.
It's not been used in 150,000 miles and I don't want to risk major expense of having to fix it should it sieze in the set postion. I ALWAYS make sure I'm parked on reasonably level ground so that I'm not putting excessive bind on transmission parts while parked. I also faithfully change my transmission fluid and filter as recommended by the manual.