The SRS light came on in my brothers 1996 300Tdi following the fitting of a phone kit about a year ago.
Having read up on it I decided going to the dealer was the only option - the light will not go off even when the fault is rectified witout plugging it in .
They said it would cost 50 which I agreed to . It took them about an hour and a half to sort it as they had to go searching for 'old' discs etc - so I reckon only they would have all the necessary gear.
In fairness to them they still only charged the 50 - they expected it to take 15mins or so apparently.
I would say that if you want it done it will probably mean a trip to the dealer . I tried a Launch and a Delphi scanner but no joy .
I did the same,wired it into the heater plug light on the dash so the srs light comes on like it should with the ignition and then goes off,passes the test no probs.
I actually admitted to pulling the bulb at my test station and they agreed that it doesnt matter as is not deemed as an MOT failure. Are we both wrong?
Just a guess but it could be it cant reset the fault not necessarily you still have the fault. Which is still annoying of course. Low voltage is a common fault and what i caused myself by letting the battery going flat slowly, after i left ignition on...........just disconnecting the battery does not cause the low voltage fault, it has to drop slowly.......or so I read........the trouble with srs and abs systems is unlike engine management systemst hey do not necessarily conform to the odbc spec, so a car maker can deliberately make it hard to fix faults without using their equipment....which they only sell to dealers of course.