Engine surge with turn indicator-1992 300SD(140)

[turnne1]

anyone have any opinions.?..I have a 1992 300SD(140) with 105k miles..Long block was replaced at 102K.The engine pulses/surges with the turn indicator and the alternator light comes on at every start up. The local MB dealer replaced a bulb in the dash(MB update I was told)..it didn't help..replaced the motor mounts...didn't help...replaced the alternator...didn't help....checked the dash cluster for shorts..none found...and btw the dash cluster was replaced in 1997....now the car is apart and they are checking wiring harnesses(and not returning my calls)I was told by the service advisor that they were having a slight problem yesterday but I would be able to pick it up today...I called three times today...and then left a message for the service manager of the dealership
All I could get was my car was in pieces because the tech had left for the day.....any ideas?....I am getting desparate...car has had almost $20K in repairs done this year(mostly warranty)

[mbdoc]

Is the engine surging or does the tach surge?? The replacement instrument clusters require a DIFFERENT alternator on the 300SD/S350D. Red fische topic # 54T94121.
Part number of alternator is 009-154-30-02-88. Digital replacement dash isn't compatable with Original alternator.

[turnne1]

Both the engine and tach surge.....about 500 rpm back and forth with the turn indicator...as far as I know this was the original alternator(I am not the original owner of the car. ...but interestingly enough the engine did not surge before the new long block was installed(about 2 months ago)....but the new instrument clsuter has been in the car since 1997...??