Magnuson-Moss Warranty Act

Can a Dealer Void Your Vehicle Warranty for Aftermarket Parts or Modifications?

Magnuson-Moss Warranty Act overview for vehicle owners, aftermarket parts, and modification-related warranty concerns.

• Their Burden of Proof: The dealer must demonstrate that the modification directly caused the issue you’re claiming under warranty.

Important Disclaimer

Vertical Doors, Inc. is not a law firm and does not provide legal advice. This page is for general informational purposes only based on publicly available sources.

Warranty rights depend on your specific situation, warranty terms, and applicable state law. For legal advice, consult a licensed attorney.

Quick Answer

In general, a dealer or manufacturer should not automatically deny all warranty coverage simply because your vehicle has been modified.

Key Legal Point Explained

A car dealer cannot automatically void a vehicle warranty just because you have modified your car. However, under the Magnuson-Moss Warranty Act, the situation is more specific than a simple yes or no.

If a dealer or manufacturer believes a modification caused damage, they may deny warranty coverage for that specific issue. In those cases, the responsibility generally falls on the dealer or manufacturer to support that claim.

Their Burden of Proof

The dealer or manufacturer typically needs to demonstrate that the modification directly caused the problem you are requesting warranty coverage for. A modification alone does not automatically justify denying unrelated warranty claims.

This is why warranty disputes involving modified vehicles are usually evaluated on a case-by-case basis, focusing on the relationship between the modification and the specific failure.

Plain Language Explanation

Installing aftermarket parts, including vertical door kits, does not automatically eliminate all warranty coverage on a vehicle.

However, warranty coverage is tied to the specific issue being claimed. If a modification caused a failure, that specific repair may be denied.

The key factor is whether the modification caused the problem, not simply whether the modification exists.

What This Does Not Mean

  • It does not guarantee every repair will be covered.
  • Improper installation or defective parts can still affect warranty claims.
  • Each claim is evaluated based on cause and evidence.

Sources We Reviewed

Federal Trade Commission – Warranties

“A manufacturer can’t require you to use specific parts or services…”

consumer.ftc.gov/articles/warranties

16 CFR § 700.10

“This does not preclude the warrantor from denying liability where the warrantor can demonstrate…”

law.cornell.edu/cfr/text/16/700.10

Magnuson-Moss Warranty Act

“The Magnuson-Moss Warranty Act is the federal law that governs consumer product warranties.”

ftc.gov/legal-library