Mark - you are asking the question under the 17025 string so I will assume you ask specifically about that standard. The only 17025 requirement that I am aware of in the auto industry has to do with testing and calibration labs. Your customer is required to verify that you, as a calibration or test lab, is accredited. Someone may correct me but to my knowledge there is no requirement for an equipment supplier to be accredited.
Having said that, if you are certifying the calibration of the equipment at the time the equipment was sold, you might fall under the requirement. (Note that if a qualified lab dosn't exist for a given piece of equipment, calibration may be performed by the original equipment manufacturer.)
I think the key here is the calibration. If you do no calibration service and simply sell a gauge to a customer which will be calibrated by someone else, then the requirement is not relevant to you.
Here comes the catch 22 - If your customer is a valued customer and says he wants you to be accredited, then the standard becomes very relevant.
As a supplier to the auto industry, you may be required to be registered to ISO-900x within 18 months. Just another thought to brighten your day.
Dave