Originally Posted by topper0108

After-market Accessories Do Not Effect New Vehicle Warranties
There’s a common myth circulating amongst vehicle owners and dealership personnel – according to some “experts,” adding after-market parts will void a new vehicle’s warranty. This is completely false. While it is true that an after-market part could cause a problem that isn’t covered under warranty, it’s against federal law to void a warranty because someone uses an after-market part.
The Magnuson Moss-Warranty Act
The Magnuson-Moss warranty act is a federal law enacted in 1975 that makes it illegal for auto manufacturers (or any manufacturer of consumer products, for that matter) to void a warranty simply because the owner of the vehicle adds an after-market product to a vehicle. The law states that manufacturers have to repair a vehicle problem UNLESS they can prove the problem was caused by an after-market part.
The Magnuson-Moss act also makes it illegal for manufacturers or dealers to require “tie-ins” as a condition of your warranty. Dealers and manufacturers can not require you to service your vehicle at the dealership as a condition of your warranty, nor can they require you to use certain brand name parts for your maintenance or repairs.
In other words, the Magnuson-Moss act says:
1. Warranties can not be voided simply because an after-market part is used on your vehicle.
2. Warranty repairs can only be denied when it can be proven than an after-market part caused the failure.
3. The burden of proof is on the manufacturer – the dealership must show that a specific after-market part caused a problem in order to deny a warranty claim.
4. When an after-market part is the cause of a specific problem, only the warranty for that problem can be denied. Other, unrelated problems are still covered under warranty.
5. The dealership or manufacturer can not require consumers to use a particular brand of part or require service to be completed at a specific location as a condition of their warranty.
Situational Examples
Example #1:
You install an after-market lift kit on your new 4×4 pickup. 2 years later, your truck (still under warranty) requires new front ball bearings. The dealership must prove that the ball bearings wore prematurely as a result of your after-market lift kit. Otherwise, they must replace the ball bearings under warranty. In this case, the dealership would likely try and show that the kit was either a) installed incorrectly or b) pushed the factory suspension beyond reasonable limits.
Provided that the kit was designed for your vehicle and correctly installed, it’s very difficult for a dealership to prove that your lift kit is the cause of your problem. Therefore, this situation would be covered under warranty.
Moral of the story: Dealers can’t just say that your after-market part caused a problem – they have to be able to prove it.
Example #2:
You install a nitrous oxide boost kit on your new truck. Unfortunately, the kit was installed incorrectly and the first use causes a major engine problem. When you take your truck to the dealership, they determine that your nitrous system was not installed correctly and therefore caused your engine problem. Because it’s clear the engine problem was caused by your after-market part, the engine problem is NOT covered under warranty.
Moral of the story: Make sure that whoever installs your after-market parts knows what they’re doing. Don’t work with an installer that you don’t have complete confidence in.
Example #3:
You pay to have an after-market stereo installed in your vehicle, the but the stereo is too powerful for your truck’s electrical system, and as a result your truck’s alternator fails as a result a few days later. When you bring the truck to the the dealership for diagnosis, they determine that the alternator failed because of the after-market stereo. At this point, the dealership informs you that any further repairs to the electrical system will not be covered unless you remove the after-market stereo.
This is perfectly legal. However, if any other parts fail on this truck that are NOT related to the electrical system – like the engine, transmission, suspension, etc. – your warranty is still in full effect.
Morals of the story:
1. Make sure that the after-market parts you install on your vehicle are designed for your vehicle. If you put the wrong part on your truck, you will have problems that probably won’t be covered under warranty.
2. Just because you have an after-market part that causes a problem, that doesn’t void your entire warranty.
Bottom line: After-market parts can not void your warranty. However, after-market parts that are either not designed for your vehicle or that are installed incorrectly can cause warranty problems. So, be sure to buy after-market parts from reputable companies, and make certain to follow use and installation instructions carefully. Follow these rules, and your warranty

Originally Posted by Ezdzit

Well here's my 2cents. I spoke to the Ford aftermarket rep that basically does the lifts and liners and etc.... He said that's as long as you use the shop they recommend the warranty shouldn't be affected. I'm sure everyone has seen the lifted trucks at the dealership, well they use certain shops of course might a little more expensive but IMO worth not having to deal with the hassle of warranty issues.