My Camry's a bit of an antique -- the 1990 LE V6. I treat the car well and keep it maintained, but my electrical/lighting system is having an obnoxious problem:

When I press the brake pedal, the driver's side rear brake/tail-light goes completely out.

I've replaced the bulb, but the issue persists. I've been told it might be a bad/intermittant ground connection, but I have no idea how to go about diagnosing it. I do own the appropriate Hayes manual, but I'm a little intimidated at the idea of rooting around under the vehicle checking wiring. Has anyone experienced/resolved an issue like this?

Best,
Ryan