Delco Audio Amplifier '97-'00

[jtj143]

Hey guys, I realize that this area is for radio mods & such, but I'm completely lost when it comes to this stuff....so just looking for some input & advice on a factory system please.
We are talking about a 1999 Suburban (classic body style) - We purchased, off eBay, a factory Delco AM/FM CD head unit that had been modified with an AUX. jack in front to run the iPod through. This worked great for about a year.
We began to notice intermittent 'dead' spots in audio output. It didn't seem to matter what the input was, CD, AUX, or radio signal - the radio would cease to produce sound.

It seems possible that the radio was somehow damaged during the modification, or it's just old...and after a year of use we noticed the decreased performance.

I've stumbled across a piece of audio hardware called an Audio Amplifier part# 16218461. I wonder if this could cause the intermittent problem?

How would you approach this problem?
How can the Audio Amplifier be tested?
If we were to install an aftermarket head unit, is the GM Amplifier still necessary?

I want to be able to play my iPod through the speaker system in the truck, and I want the dash to look nice.

Help....suggestions.....advice?? THANKS!!!