2006 Mini Cooper s r53 here. Recently replaced the alternator. Next I did the struts w complete new kit front and back. All brakes and rotors. Worked great. Then it started to overheat at idle. Battery also died and turned out to be bad as well. New battery and also changed the thermostat and did a coolant change. Changed out the expansion tank as well because it looked like the seam had cracked. Temp at idle is all set now. Driving home from the test drive the engine light, abs, asc lights all come on. Then the battery light intermittently and it would lose power. Sometimes the whole thing would seem to go away and restart with no lights for a bit. Then they would all come on again. Turning onto my street the exclamation light also flashed.
I know I have to check the codes and everything but could a bad ground somewhere be causing all this?
Any help would be appreciated.