I have the same problem on my 2000 Breveda. Other forums said turn signal level (2001 s10) or tail light circuit boards chevy venture.

2000 Blazer brake light issue. Only Middle brake works. Same problem last year and had the sensor replaced. This time, replaced sensor, all bulbs and check all fuses, still only middle brake light works....Thanks for your help

We bought a 2000 Blazer in '02 and one day I noticed there were no brake lights, but the 3rd light on top worked fine. I did some research online and found out there was a recall on this problem due to the hazard switch on the column. I also found out if I wiggled the hazard switch a certain way, the brake lights worked. I was able to get by for awhile by wedging a 'widget' beside the hazard switch button and the hole in the column cover. This worked fine until someone would knock the widget out of place. I finally got around to having the switch replaced at a local dealer. All was fine until last week when I was told the brake lights were out again and I found out my hazard lights didn't work either. I changed out the switch assembly myself this time, and once I had it out I saw what happened. The brake light voltage comes in to the assembly on a white wire, and the first contact this goes through is on the hazard switch. In my case the contact had obviously overheated from the brake light current and melted the plastic holding the contact in place, thus breaking the circuit to the brakes. Either a poor design or too much current for the circuit to handle. Soooooo now I am in the process of replacing the four bulbs in the tail/brake light assembly with 3 watt Luxeon LED plug-in replacements. The current draw of the original bulbs was measured at 2.2 amps at 13.8 volts, times 4 bulbs makes about 8.8 amps that goes through the contact in the hazard switch whenever the brakes are stomped. The LED replacements draw .2 amp each, so times 4 will be .8 amp or less than 1/10th of the original equipment bulbs. These LED bulbs in my opinion are as bright or brighter than the original equipment and hopefully will help from burning out another switch assembly.. David