Toyota Repair: shift lever stuck, brake light switch, toyota camry

Question
I have a 98 toyota camry le v6 3.0  automatic.just recently as the weather got colder the shift lever is stuck in park upon early morning initial start-up.depressing the brake is necessary to unlock the shift lever but seems spongy at first and depressing it as far as possible doesn't help. after driving a short distance ,I confirmed at least the brakes feel fine, the lever shifts without problem after a good warm-up.I have not dared to put it in park when it is still cold for fear it will be stuck again. Outside temps are in the low  thirties at night. My brakes have been squeaking for a long time even though I have plenty of pad and even replaced the front ones.they squeak almost all the time .I pull the e brake while going slowly when I hear the noise and it goes away. please tell me what could cause the condition with the shift lever. I am not concerned with the squeak ,just included that in case there is a coralation.I am knowledgeable enough to do a brake job. By what means does the brake pedal lock the shift lever in place? mechanically or electronic or a combination or does it have a brake fluid pressure sensor? brake fluid is maxed.
repair history: short block replacement a few thousand miles ago.front pads replaced upon purchase a year ago. help!  

Answer
The shift interlock solenoid is located inside the shift console, the most common cause for this is that some kind of soft drink was spilled into the console, the sugar causes the solenoid to stick.
The solenoid receives an electrical signal from the brake light switch and releases the interlock under normal conditions.
The solution to the problem is to remove the center console and the shift indicator assembly and either clean or replace the solenoid.
In the meantime should you get stuck and not be able to get the shifter out of park, there is a small cover just in front of the shifter, remove this cover and push a pointed object like a small screwdriver or even the pointed end of a key in the opening, this will override the shift interlock and you can get it out of park.
The brake fluid level or pressure has nothing to do with this.