I have a brake light problem that has me stumped. Sometimes the brake lights only work on one side or the other and sometimes they don't work on either side. I checked the bulbs and they looked good but I replaced them anyway and when that didn't help I replaced the brake light switch. When that didn't help I replaced the tail light circuit boards and that didn't help either. Has anyone here ever had a similar problem with a C1500 Chevy truck and can you tell me what you found causing the problem?