Electrical problem
1996 Cadillac SLS V8 Front Wheel Drive Automatic 79800 miles

Shortly after we bought our Cadillac the service engine soon light came on. On our digital display it read "srevice electrical system". We took it to our mechanic he put it on a machine and a code for the evap system came up. He said he thought it was a sensor. He stated it was no big deal. We tried changing the gas cap. That didn't work. Then we had problems with the trunck motor. Our mechanic put it on the machine again, and nothing came up. However our service engine soon light is still on. Now we have a reading that says"service ride control". The entire time the sevice engine light has been on, which has been 3 months, it has always read service electrical system. No one can seem to find anything wrong. What is going on?? Please help!!!