I have a 1998 Chevy 4 Dr Blazer. A few days ago I noticed my parking lights were on in the middle of the night. No headlights were on. Got in the car and her the door chime like I left key in ignition. Started car no problem. Turn car off lights went off. A few days later it did it again. This time I started car and drove it around and parked it but lights would not go off. I went to autozone and checked fuses and say RR park light was blown. I checked it and the fusee in. I stepped on brake and noticed a loud sound starting to come from under hood, almost like a constant buzzing sound stuck on. step off brake sound went away. Drove home got into my drive way and sound was going constantly now and the brake lights were stuck on. Turned off car and brake lights would not go out as if i had my foot on pedal. sound is not going off either. I had to pull the negative battery cable. Before pulling cable looked under hood and saw the sound is coming right near the front left car light under the air filter almost.

Any ideas?

 

I have a similar problem. I have a 97 S10 blazer and every time i brake i get a low buzzing sound but i have no idea where the sound comes from but my brake ligts work perfectly. Sorry Wish i could help.