QuestionHi Brian: I was impressed with the way you answered forum questions and thought I'd give this a shot. My '03 Dodge PU has a factory Infinity sound system. It was blowing fuses in the fuse box and I isolated the problem by unplugging the amp under the dash. Whew,,,, what a job. My question is two fold. Is this a for sure way of knowing that the problem is in the amp. and how do I replace it ( without going to factory OEM for high end pricing ). Thanks so much and I anxiously await your answer.
AnswerHi Sid,
Was the 20-amp "Radio Amplifier" fuse in the engine compartment fuse box the one that was blowing?
It seems likely that an internal defect in the amplifier was causing the problem, especially if the fuse isn't blowing with the amp unplugged. That would rule out a short on the amplifier's power wiring. However, the only way to know for certain would be to connect a substitute amplifier.
A stock Infinity amp can't be easily replaced with an after-market amplifier; the number of output channels, as well as the built-in crossovers and equalization in the stock amplifier are designed to work specifically with your truck's speaker system. If you want to keep all the stock speakers working, you'll need an OEM amplifier.
The factory radio in your truck uses high level outputs. This means that, unlike some other types of OEM "premium" audio systems, the stock head unit is capable of driving speakers directly without the amplifier. You could bypass the amplifier plugs, by finding the source wires coming from the head unit, and connecting them directly to the output wires leading to the speakers. However, the head unit isn't capable of running all the speakers in the truck; you could connect the front and rear door speakers, but you'd have to give up the dash speakers.
Otherwise, you can often find used OEM amplifiers on eBay for quite a bit less than you'd pay at a dealer's parts department.
Hope this helps!
Brian
