The Magnuson-Moss Act
Protecting tweakers, tuners, and other users of aftermarket equipment. 

FANNING FEARS 
You want to upgrade your vehicle with aftermarket equipment, but you’re 
worried about putting the vehicle’s warranty at risk. It’s no wonder. How 
many times have you heard someone of a dealership say that installing 
aftermarket equipment automatically voids the warranty? This common
misconception has been repeated often enough to be widely
believed – though it is completely false.

Fact: Dealers don’t like warranty work, because it pays less than normal 
repair work. By promoting the myth that aftermarket equipment automatically
voids warranties, some dealers avoid such low-paying work. Instead, they 
attempt to charge customers the prime service rate for work which is
rightfully done under warranty.


THE TRUTH

Most vehicle owners are not aware they are protected by
federal law: the Magnuson-Moss Warranty – Federal Trade Commission 
Improvement Act of 1975. Under the Magnuson-Moss Act, aftermarket equipment 
which improves performance does not void a vehicle manufacturer’s original 
warranty, unless the warranty clearly and conspicuously states that 
aftermarket equipment voids the warranty. Most states have warranty statutes,
as well. Which provide further protections for vehicle owners.

In other words, that means a dealer can’t wiggle out of his legal warranty 
obligation merely because you install aftermarket equipment. To find out if any 
aftermarket equipment automatically voids your vehicle’s warranty, check the 
owner’s manual. It is likely the language you are looking for appears under a
heading such as “What Is Not Covered” Although the language seems negative, 
remember your vehicle manufacturer is simply saying he does not cover the 
aftermarket products themselves. He is not saying that the products would void
the vehicle warranty.


VEHICLE DEALERS OBLIGATIONS

Suppose your modified vehicle needs repairs while still under warranty. 
Without analyzing the true cause of the problem, the dealer attempts to deny
warranty coverage. He made his decision simply based on the fact that you’ve 
installed aftermarket equipment – a convenient way to dodge low-paying warranty work.

An example of how ridiculous this can get is the man who was denied warranty 
coverage by a dealer on his power door locks, because he had improved his 
exhaust system! Sounds nuts? It really happened – because that man did not know
his rights and challenge the dealer’s decision.

Fact: A dealer must prove – not just say – that aftermarket equipment caused 
the need for repairs before he can deny warranty coverage on that basis.



YOUR RIGHTS

Point out to the dealer the provision of the Magnuson-Moss Act- Require that he 
explain to you how the aftermarket equipment caused the problem. 
If he can’t – or his explanation sounds questionable – it is your legal right to 
demand he comply with the warranty.

Fact: If you are still being unfairly denied warranty coverage, there is recourse. 
The Federal Trade Commission, which administers the Magnuson-Moss Act, monitors 
compliance with warranty issues. Direct complaints to the FCT at (202) 326-3128.

DODGE MOTORS
“Certain changes that you might make to your truck do not, by themselves, void the 
warranties described in this booklet. Examples of some of these changes are: installing 
non-Chrysler parts, components, or equipment.” – 1997 Warranty Information supplement to Dodge

Owner’s Manual:
GENERAL MOTORS CORPORATION
“If a Chevrolet part fails due to a defect in material or workmanship not related to 
(on aftermarket products) or the labor to install it. Chevrolet would be responsible 
for covering the failed part.” – Chevrolet Customer Assistance Center

FORD MOTOR COMPANY:
“Installation of a non-genuine Ford item does not, in and of itself, render warranty 
void.” – Ford Owner Relations Division
FEDERAL LAW

‘In order to improve the adequacy of information available to consumers, prevent 
deception, and improve competition in the marketing of consumer products, any warrantor
warranting a consumer product to a consumer by means of a written warranty shall. . .fully 
and conspicuously disclose in simple and readily understood language the terms and 
conditions of such warranty. Such rules . . . require inclusion in the written warranty 
of any . . . exceptions and exclusions from the terms of the warranty.’ – Magnuson-Moss
Warranty & Federal Trade Commission 
improvement Act. Section 2302(a)