Hello, in our longer search for a W140 we have now found a S420 from 1997. Well equipped, 169,000km. Actually, the car is top – only clack the hydro plunger light. Does anyone have an idea, a) what this can come from and b) how expensive a repair would come, if there is nothing else? What can such a car cost taking into account the mentioned lack (the seller wants approx. 6000)? Equipment/ Data: 1. hand, automatic, air conditioning, driver airbag, sidebags front, passenger airbag, driver and passenger seat electr. adjustable, ABS, drive loop control, window lift electric 4-way, seat left/right orthopaedic, radio/casset, immobilizer, outdoor temperature indicator, servo closure, color glazing, exterior mirror foldable, servo steering, central locking with remote bed., wood equipment noble wood, alarm system, Tempomat, aluminium rims, 3. brake light, , fog lamp, thank you, your Joe.