Dear Clem-- That light comes on whenever the traction control feature on your 1999 Volvo V70 has been activated. The traction control is in the ready position whenever you turn your Volvo on and it is designed to temporarily transfer power to the opposite wheel if one tire hits a slippery spot. It happens in the blink of an eye and if the light didn't come on you might never know that the system helped you to avoid skidding and perhaps an accident Good luck from Bovan.
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