2005 Limited Roadster 6 speed manual White. 72k miles. While engine running but sitting still, if I press on the brake pedal hard the ESP & BAS light comes on and stays on until I restart the car. I bought this car with a salvage title with 45k miles with light rear end damage. This condition was present when buying the car. When normal diving the light only comes on if braking hard. This then disengages the cruise control. Could this be a faulty Brake PRESSURE switch or is it a bad BAS unit?

 

You need to get the computer scanned to know for sure. Otherwise you are just guessing.

 

Scanned with OBDll scanner and no codes. Haven't scanned with DRB III scanner yet

 

There are other scanners other than the DRB 3 that can read it. It sounds like you need a brake light switch but make sure you get one for a manual transmission because the automatic ones are more commonly sold.