I am new to the forum and have a question that may have been posted before. I have a 1998 Chevy silverado 3500 and my brake lights are not working ( including 3rd light). Have changed the brake switch , relay under the hood and checked the ground. Took it to my mechanic for some other reasons and asked him to look at it. He had the truck for a few days and the brake lights worked while he had it.

Picked the truck up today and drove around for a while and checked the lights and they didn't work. I plan on taking it back to mechanic but am posting question anyways.

Any help would be appreciated..

 

Thought I had a short in my brake light. Have replaced the bulb several times. My mechanic told me it wasn't in right!