I purchased a 99 s80 and when I picked up the vehicle the driver side window, driver side switches, radio, power seats, and a few dash lights like the oil, etc stay lit always. The screen to the left displays "brake failure stop" but the brakes are fine. I took the car back to the small dealer where I got it and the guy is telling me that the car needs the ecu or something replaced to fix the issue and that he's waiting for one to replace it. Well it's been 2 weeks and he hasn't called so i'm assuming he screwed me. Before I take it any further (legally) i'd like to try to fix it myself since I love the car.. any suggestions on what causes that electrical glitch? I checked the fuses and their all good.

 

First I would call him back and see what is going on.

Second If nothing happens in 1 then I would have to guess without seeing the car that the ABS module is bad.
You can get yours rebuilt for pretty cheap.

Also you might want someone that knows Volvo's pull the codes and see what they are to be safe.