Interesting point there. In the modern world, no component stands alone, it is part of a system. For instance my car has a charging system and a "maintenance free" battery designed to be part of the car electrical system. Every part is designed and warranted by the manufacturer to work together as an integrated whole.
When a few months ago my car battery suffered a total failure (wouldn't turn the engine) I noted that it had a 60 month warranty. I took the car to the dealer, who tested the battery, said "yup, the battery has failed", and replaced it with a new one no questions asked. Someone, somewhere, had calculated that the recommended battery installed in that system ought to last 60 months without failure, and that they would not lose their shirt if they wrote that on the warranty.
If you are supplying an individual part that might be installed in a system you have no control over, then you absolutely have to make this at the owner's own risk, due diligence expected, no warranty implied. You must make it very clear that the purchaser is responsible for any consequences of installing the part in their vehicle, and if they don't want to be responsible they must not purchase your part. I'm sure this comes up a lot in the enthusiast/hobby/restoration world. You might consult a lawyer for advice (although I know that will cost an arm and a leg, unfortunately).