Hi, I have a 2000 A8L 4.2 (d2) and reciently encountered a problem with my cruise control not working and a flashing red BRAKE light on the dash. All fuses are fine (in the fuse box under glove box location) and the flashing red brake light on the dash starts flashing as soon as I start the car. I assume whatever is causing that problem is preventing the cruise control from working?
Any help or insight will be greatly appreciated

 

Hey, I'm new here, and I mainly have experience with BMW, but I think I can help. On my car, the cruise is dependant on the abs sensors to accurately determine the speed. When my wheel speed sensor went out, my cruise wouldn't work. It could be an issue with the abs module, abs sensors, or perhaps the wiring. This is just a starting place. Since your car is about the right age to be running a Bosch 5.7 abs module(well known for cold joints that break) I might look at that. I like to start with the cheapest thing and work my way up from there. I will say steer clear of the Chinese abs sensors, I have not had any luck with them. If you do have an abs module issue, your best option is to have it rebuilt by one of the services on eBay, it's under $100 and I can give you a discount code. Diagnostic software is worth its weight in gold, or many places will diagnose for under $100

 

Check/replace your brake switch. Located on the brake pedal arm. You need to take off some trim to get to it.