At the bottom of this post is the wiring diagram I am working with. Highlighted is the brake switch wire path; which shows it is connected to a leg off a relay I am looking for.
The problem is not the switch, the fuse or the lights. All the brakes are working when the pedal is pressed. We have followed all of Ross-Tech's wiki information and confirmed it is not the switch. The 100% positive way that we confirmed the switch is not the problem is we removed it from the car and took a reading. With the switch removed, we should see Group 6 Bin Bits read 000. We see 010. (The last 0 successfully changes value when the switch is installed and the brakes are pressed.)
This means the computer is seeing an errant signal, not coming from the brake switch.
The next troubleshooting steps is to wire trace and see what can be sending that errant signal. From what I see on the wiring diagram below, since the one of the brakelight switch wires is connected to a leg of the Low Heat Coolant Preheating Relay (M/T), that relay could plausibly be sending the signal. The relay is almost 20 years old. However, I cannot locate where this relay is and searching the forum and Google is not yielding any results.
The next plausible items to check would be the High Heat Coolant Preheating Relay (M/T) as the BLU/YEL wire loops over. The Clutch Vacuum Vent Valve Switch is also connected to the same leg of the Low Heat Coolant Preheating Relay (M/T) and is also about 20 years old along with the PCV Heating Element connected via the sam BLU/YEL wire. At the moment, I choose left to right when troubleshooting items.
If all of those check out, then it is something on the control module or broken wires crossed or shorted. Fingers crossed its one of these. But I won't know until I can find it, pull it and test it.
