Brake light on instrument cluster
 

I know the bulb for "brake" on the instrument cluster is good, but I have never seen it on. I tried hitting the emergency brake, that does not make it light up. Is that light tied to the proportioning valve? What does make it light up?

EDIT: From reading the owners manual it appears it will not light up unless the emergency brake is on an the key is also, on, going to try that.

EDIT2: With the emergency (parking) brake on and the key turned to on, still no brake light on the dash.

Take the wire off the valve or parking (emergency) brake and ground it with the key on. If the circuit is good it should light up

Should the car need cranking? I am about to bleed the brakes anyway, so I will be right there at the valve.

The brake light is turned on during two events: when the emergency brake is engaged, and/or when there is a loss or reduction in system pressure. It's tripped by a switch that the e-brake contacts when depressed, and is tripped by the sensor in the proportioning valve like you said.


The parking brake switch is under the dash and is contacted by a bracket that's bolted to the parking brake pedal when it's depressed.

Turn the key to the 'ON' position, engine doesn't need to be running.

Yeah, could possibly be a wiring issue then. But I will investigate further.

Well the issue ends up being that the prior owner let the master cylinder leak really bad. All the brake fluid was pouring down the proportioning valve and ruined the connector.

Brake dash warning lamp
 

On that warning light, the bulb is + power on one side when you turn the key on and I am sure that it is fused. I am thinking check the fuse marked "gauges" in the fuse block. Then the other side of the bulb gets grounded to light it up. Normally it is not grounded unless you need that bulb to light-up. As said above you only have 2 things can ground the other side of the brake light warning bulb. Do keep in mind that these cars were only designed to last for about 10 or 14 to 15 years max.

Both the + power and the ground for that bulb pass thru 2 items which can go bad from years and heat from the sun. The printed circuit and those plastic sockets that twist in. In all 2nd Gen trans Ams Those dash cluster sockets take a push-in bulb to speed assembly however the inside contacts are made from brass. I have noticed that after about 15 to 20 years the brass will develop an invisible film of corrosion that can block your current passage to the light bulb(s). The tiny wire tangs on the base of the bulb tend to rust and/or corrode.

Once per each 20 years time span it is a good idea to remove all of those sockets and clean the inside & replace all of the light bulbs.

Also clean the socket outside tabs that press into the copper footprint(s). The printed circuit itself may need replaced as well due to the passing of many years. Heat and time; those will peel apart or the many copper pathways sometimes pull loose off of the mylar backing.

I did actually replace all the bulbs, sockets and the circuit board. I am still tracing down small issues, but I will be circling back to this.