Mercedes Benz repair: mercedes 180e, crank sensor, heater coil

Question
QUESTION: ive just had the heater coil changed apparently their behind the dash , well now the car stalls in traffic , at lights and it has become very dangerous , what can the problem be?

ANSWER: did the car work fine before then?

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QUESTION: yes the car worked perfectly ,up until 2 weeks ago there was no problem i discovered that after the heater coil was replaced the car began to stall at traffic lights and whilst driving as well , i have been told that this problem is not common but that it has happened before with the same kind of model i believe it might have something to do with the dash been removed and maybe wires have been disturbed can you please find out for me what could be the problem so i can rectify as soon as possible before i or someone else gets hurt or injured..... thank you.

Answer
what made you replace the heater coil??what year is it is it a c class. Kind of hard to tell you an exact answer on your problem. You first best bet is to run your car with the air cleaner off so it has straight air going into the throttle body it will trigger off your check engine light ..Otherwise I wouldnt know why they would tell you your heater coil needed to be replaced. I would take it back to the person and tell him the problem. Does it short out all the time even when the heater is off? Check your coils obvoiusly..and make sure your alternator is up to par along with your battery cables.Does your temp gauge fluctuate from 80 - 100 in stop n go traffic ??what is the temp normally running at?? if it fluctuates chances are your fan clutch is shot but that would just make your car overheat seems to be maybe a crank sensor or something elso .If you have an autozone and it is obd2 have them read your codes then get back to me .