brake warning light question.

[92EcoDiesel Jetta]

The brake warning light does not work in my 92 Eco instrumenr cluster. I have 2 spare clusters and could not get its brake lights to light up on the bench (power supplied to cluster and grounding the brake warning input).

Is the brake warning light an LED or incandescent bulb? I can't imagine how 3 clusters have burned out brake warning lights if they were LEDs.

[92EcoDiesel Jetta]

I feel kinda dumb.  Turns out the reason I could not get the brake light to work on the bench is that there is no brake light on the Ecodiesel cluster! It's in a separate module along with the seat belt warning in the dash and the connector to it was unplugged! Plugging connector back in, brake light still did not illuminate. Took the module apart and found the bulb (incandescent) burned out. I soldered in a new bulb and will install the module tomorrow.

What led me to all this was a low brake pedal, which led to finding no fluid in the reservoir! I would have caught it much earlier if the brake light was working!