R129 ASR fault

[bigmal]

Hi Guys. My car SL 500 129 1995 48k miles. It was booked in to Mercs for the replacement of the fuel overflow pipe. Whilst under their charge the service guy reported that the ASR light was showing. I pointed out this was not the case when I brought it in. When I went to collect the car on Saturday the light was still on. I have left the car with the dealer and I am expecting healthy discussion on Monday, when the guy dealing with my car returns to work. Does anyone have an idea what (if anything) they may have disturbed? Or where the unit that controls the ASR is situated in the car. It would not be somewhere close to the fuel filler by any chance?
Any thoughts/comments would be appreciated
Thank you
Bigmal

 

[television]

Probably the sensor on the diff as they have been working on the rear end

 

[bigmal]

Sorry for the delay in thanking you, for your input. I have been away for a few days. Just to complete the loop, so it may help others the fault turned out to be an over tight accelerator cable.