Use the following diagram to diagnose and cure the most common noise problems associated with systems with outboard amplifiers. The idea is to isolate the specific cause of the noise so you can eliminate it. For a more detailed explanation on how to eliminate noise, see our Car Audio Noise Suppression Guide. If these tips don't solve the problem, it's helpful to be able to call on a Crutchfield Technical Advisor. If you purchased your gear from Crutchfield, or purchased tech support separately, you can contact them toll-free between 8 a.m. and midnight Eastern Time, seven days a week.

Before you get started, you should first check your vehicle's electrical system.

• Check the battery fluid level and fill, if necessary
• Make sure the battery leads are tight to their posts
• Make sure the battery's negative-to-chassis ground cable is sturdy, intact, and tightly secured