Car Stereos: 2003 silverado radio amp wire location, fuse size, glass fuses

Question
Justin: I would like to install an amplifer (for a subwoofer) on my 2003 Chevrolet Silverado. This is a base model pickup with a factory radio. There is a 30amp fuse contained within the main fuse box under the hood. It is always hot (key off) with 12volts on one side. I can't tell if there is a wire connected to the other side; that would require disassembling the fuse box which I am reluctant to do. What color is the wire and where does it lead to or end. I can follow the wires thru the firewall to under the dash but beyond that I need help. I would like to tap into this wire to power the amp. Thanks, Richard.

Answer
Hi Richard,

I wouldn't know off-hand what exactly is running off of the wire.  Being 30A and going into the dash is extra confusing, since most things that require large power draws are under the hood and only powered by a solenoid on a relay (such as the starter).

Regardless though, if you want to install an amplifier, the smartest thing to do is to run a fresh new power wire to the battery into the trunk, and put 2 inline fuses on it.  One under the hood, and one in the passenger compartment or trunk.

The reason for this is if the current item hooked up to it has a 30A fuse, then it's expected to draw a good percentage of that already, and amplifiers are large power draws, and would likely pop the fuse.  If you increase the fuse size, you're likely dealing with a) wire that isn't rated to handle that much load, and b) the possibility of a fault of whatever's already on that fuse drawing enough electricity by itself to require tripping to prevent electrical fires and/or damage, but wouldn't happen because of the increased fuse size.

I'd suggest a new power wire (either 8 or 4 gauge, depending on just how much your amp draws), and putting inline glass fuses on it equal in amperage to the fuse the amplifier comes with out of the factory.

Justin