Waz up my caddi peoples! I recently purchased an 88 cadillac eldorado and the engine control system light comes on some time in the dashboard and the message service soon is stated in the driver info center. What exactly is the the engine control system and is it costly to have serviced. Also I am not getting any heat from my vents just my defrost on the top of dash. Somebody please tell me what the heck is going on.