It's at the brake pedal.

You just answered a thread that was a year old....

OK... 6 1/2 years late on the answer... Hopefully this can help someone else with this old beast-of-a-car. Sounds like you had a problem on the dash instrument panel circuit board. There is common logic area that controls the lights for the 4 doors, trunk and Brake Bulb (safety indicator) lights. The logic is; all 6 bulbs turn on for 5 seconds after turning ignition on, while you get that beep beep. If they are all coming on and staying on, Ill take a guess and say you have a problem with transistor TR71 shorted to ground, or (unlikely) the HIC71 (12 pin inline thingy) is holding Pin 8 high.

Another option is a bad alternator/low voltage situation. I say that as I had the alt belt off while running the engine before, and all 4 doors and the trunk lid ajar/open light were on. Once I had the battery charged, and the alt belt reattached, those lights turned off. I should also mention that the dash was lit up like a Christmas tre with ALL of the warning lights being on.

that's true if all dash lights come on, however the original post was specifically for the door/brake bulb check lights (safety indicators). It's the lower right side of the instrument panel, and those bulbs share a common circuit area