Brake Light Malfunction

I have a 99 Express conversion van that has a brake light that doesn't work properly. The center and left side brake lights work fine, but the right acts strangely. With the running lights off, the running light filament will light when the brakes are applied (not the brake light filament). With the running lights on, the running light filament is on as it should be, but it goes off when the brakes are applied (and the brake light doesn't come on either). All other lights seem to be working fine. With the brake light bulbs removed, the contacts in both the left and right side sockets seem to be acting the same when the lights are on or the brakes are applied. The ground appears to be functioning correctly, also. Any ideas on what could cause this situation?

I have a 2000 Express and have the same problem. I took it to the dealer and they said the light socket is bad. They wanted $200 to fix. I took the light assembly apart and wiggled the wires while my daughter applied the brakes and turned the lights on and off. I got the problem to go away when I placed the wires in a certain configuration. Must have been a short. If it happens agin, I will order the socket and replace it myself.

That seems to indicate a bad ground connection. The running light might be a bit dimmer due to the current flowing through the stop filament to ground. When you apply the brakes the 12 volts goes to both filaments, so no current flows. The source of the bad ground can be the socket, a wire or the actual ground point for the light assembly. If Chevy can charge $200 for something like this I must be in the wrong line of work!

I have a 2002 with the same problem. I have put it off trying to get it fixed because if the dealer service says 2 to 2 1/2 qts of oil per 3000 miles is within GM's specs I could only amagine what they say for this little problem.:uhoh:

It is a very common problem. Just go to your local Advance Automotive, and get a replacement harness - yes, they have them. It's $25, and comes with both sides. The one I bought was made wrong, and had the white and brown wires reversed at the plug, but worked fine after a quick fix.

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