It may surprise many of you, but the OEM does not make most of their parts. Standard, BWD and especially Wells(Autozone) manufacture the sensors and switches found on your vehicles. I've opened many boxes and found where the OEM numbers are machined off as not to violate any copyright laws. No question the quality of parts has taken a nose dive on the slow boat from China. I also sell OEM AC Delco and Motorcraft parts and have seen the defect rate increase there also. Read the package on the OEM parts and see how few made in USA partsyou can find.
As for Rock Auto, they have their uses in parts world. I've picked up a few items in clearance real cheap and the bonus being they are almost always old bought up inventory that were made in the USA. But if you have a vehicle down, why would anyone buy from them and wait a day or three to get your part. Buy it locally, either at the dealer or parts store and get back on the road in a few hours (unless you get a defective part! GRRRRR!)