hounddog

we have a 1988 300TE 209,570 miles. starts and runs great, at idle the oil pressure is at 2.5 bars, at 1000 rpm, the oil pressure goes to 3 bars. we had the oil(shell rotella 15w40) changed at 207,400, new mann spin on oil filter. everything seemed great, then we started the car and the idiot oil light came on. the line to the sensor on the iolpan was disconnected, and reconnected. the mechanic at the time said it was nothing, the oil level on the dipstick has remained the same, just changing color, just doing it's job. is this a common problem with gas driven mercedes? we had a 1982 300TD wagon for 10 years, no oil idiot light problem. could it be the oil sensor in the oil pan ? all the fuses are fine, guess i'am getting tired of the#%&*^%$ idiot light on, guess it's just something simple hounddog in winchester, va