Why would only the center brake light work and not the left or right brake lights When the bulbs are good
Stop brake lights on 2001 Chevrolet Express 2500
The brake lights on your 2001 Chevrolet Express Van work as follows: Power for the left and right brake lights goes from the brake light switch through the turn signal switch to the rear lights, power for the center brake light does not go through the turn signal switch. You could have a faulty turn signal switch, connection at the switch, or two faulty light sockets in the rear. Testing the circuit from the brake light switch, through the turn signal switch, to the rear light sockets is the only way to determine the cause of your side brake lights not working.
buy a turn signal switch from a cheap source, plug in under the dash without installing, check to see if the side lights work, if they do - turn signal switch, if not - return it & find the real problem. it's highly likely to be your turn signal switch
If the brake lights (not 3rd center)and tail lights work indepentently,but not at the same time bad bulb sockets.splice in NAPA replacements(part#LS6505 $22.00ea)worked on my 2001 chevy express van.
This happens on A LOT of chev express vans. Most of the time it is the ground (common) wire to the bulb socket. That socket has 3 wires. One is energized when you turn on the parking lights, the other is energized when you step on the brakes. The third wire (black) is the common wire that is connected to the sheath of the bulb. This allows the current to flow through either of the bulb elements to light up. Without the ground, electricity does not flow, and voila, no light.