Kyle;

The Brake failure indicator is not tested in the Ignition ON position of the key before starting the engine (so unless you have a brake failure you NEVER light it), but you can easily check it by disconnecting the control wire from the differential pressure sensing valve under the hood (follow brake lines from master cyl.) and grounding it to chassis (IGN ON).

Use a test light to check for power starting at the Dimmer control...these often go intermittent after years of not being touched.

Good hunting