I have a brake light problem that is whenever I apply the brakes, only the 3rd brake light comes on.

I don't think it is the brake switch because the brake lights must be getting a signal if the 3rd brake light is responding.

I really do not think all the bulbs blew at one time.

I checked the fuse and it's fine, and the hazards are working fine (run off the same fuse).

So I imagine the only probable culprit left would be a bad ground. The problem is that I am away from home and don't have any manuals with me. Can anyone please help me out by guiding me where the main brake light ground is located?

Thanks.