My 2000 deville has had some weird issues in the past year, but for the past two weeks it has been running really rough when it is first started and yesterday after about 5 minutes of driving the DIC said the car was overheating but there was no actual sign of it overheating (no steam, no water, no hard hoses, etc.). In the past year it has been telling me to fill my coolant and washer fluid and they are full. My gas gauge is fiction, my rear heater doesn't work, the light under the hood didn't work until the car says it overheated. Not sure if is related or not, but I went to the car wash and 15 minutes later is when the car said it was overheating. The gave me codes P1536 (ac issue) B1004 ( KAM) C0663 ( ride level issue). Nothing that has to do with my current issues. My Scan tool says no link and turns on the security and traction control lights. I am thinking maybe the bcm? Any thoughts on this?