The general rule in the U.S.
In general, a dealer cannot void your whole warranty just because you added an aftermarket part. However, if an aftermarket part or installation causes a problem, the repair for that problem may not be covered.
That is a general statement, not legal advice, and your warranty paperwork has the details.
What good installers do
A careful install uses vehicle-specific interfaces, makes connections that do not cut factory wiring and leaves the vehicle in a condition a dealer can service. Ask your installer to describe how they make connections.
Ask the right people
Your dealer can tell you what they cover. Your installer can tell you how they work. Your warranty booklet or your manufacturer’s website has the formal terms.
A calm way to ask your dealer
Call the service desk and ask: "If I add an aftermarket remote start, how do you handle warranty questions?" Most will explain their policy plainly. Keep the answer and your installer’s paperwork together.
Quick answers
Will remote start void my warranty?
In general, no, but damage caused by a faulty install may not be covered. Ask your dealer for your vehicle.
Should I tell my dealer?
It is a good idea to mention it when you service the vehicle.
