You might spread out your question to sites like Toyotanation. Do recall reading something like this problem at their site.

 

I've looked over there as well, but you've more of a reliavle source. I too am having this problem. I just replaced the whole rear harness from the blue connector on back. I didn't grab the harness for the trunk lid, not sure why not, but since that's where the flexing would occur, most likely there's a problem with that harness.
Though there are different models of the lamp failure sensors. I've heard you need to match one to your vin to be really sure if it will work.
Well let us know what you find out. I've been puttering with this for over a week now, and feel like just getting rid of the headache. Though it more than likely is something simple, to replace.

 

Update #2: Well, my warning light is back. God da^^n it! I suspected that it had something to do with brake lights because the warning light turns on after turning the ignition on then pressing the brake pedal. I found a smoky tail/brake bulb (still working) so I replaced both of those. That did not clear the warning. I'll try the 3rd brake light next and let you know what happens.

These sensors is just too god da^^n sensitive.

 

I'm having this probelm too.I have an 99 LE(the Gauge Cluster warning light is on).when i turn the car its off but once i put the emergency brake down thats when it gose on! I've check all rear taillight bulb and the rear license light bulb(and changed them)!

 

Are you sure this is not the E-brake light indicator?

 

Yes i'm sure its not the E-brake light indicator! I'll take a pic of it tomarrow!

 

If E-Brake on, does the brake light also come on?

 

Ok here's the Pics!
This one is after I turn on the Car Before I release th E-brake!

Here's After I release the E-brake!

A Closer Look.

 

Suggest you do the easiest things first.

It is possible a bulb could be failing or a socket could have corroded terminals (but bulbs still light up) and the sensor was triggered. In some cases one filament in a dual filament bulb breaks and lies against the other filament causing strange electrical issues.

Suggest you replace all the bulbs and clean the terminals. The sensor monitors all brake and rear taillights.

If this does not fix the problem post back.

 

What do I use to Clean the Terminals?