Q I installed a New Pioneer system (head unit, new speakers & Premier amp) in a '99 Chevy Suburban. What happens is as I turn the volume up about 1/3 I get an attenuated/muted signal for about 2 seconds, then it will go back to normal on its own. It also happens if I turn it down a click. Sometimes I can turn it up higher before it does it. The previous owner said it did a similar action with the factory system with a small Jensen amplifier pushing his sub wired in stereo. What's the deal?ThanksAJvia the Internet
A This is an interesting troubleshooting scenario due to the global changes that have taken place; rather than local isolation. Statistically, this makes it much harder to point directly and quickly to the cause of the problem. The first step in troubleshooting is to visualize the system and what areas are the most likely to be affected based on the characteristics of the symptom. For instance, if your tire keeps going flat, you would not start by investigating the air conditioning - they are not related. Another possible cause might send you to a scale to confirm that the vehicle is not too heavy. This one is far closer in likelihood than the air conditioning as a source of the problem, but is it a reasonable possibility? Not likely, since you would notice a major difference in acceleration and handling if there were that much excess weight. You would first look at the symptom and ask "When does this happen?" and "Does it also affect the other three tires?" That immediately isolates and reduces the list of possibilities to a few areas of investigation.
The same style of abstract thinking goes into troubleshooting the mobile electronics products in a particular installation. Possibilities in your situation can include an amplifier that has a stability problem in that it doesn't respond correctly to changes in state, meaning that when you ask the amplifier to produce more output, it "stalls" for a moment. To prove or disprove the amplifier as the source of the problem, you would perform a few quick tests. One of the most common "quick checks" for a professional installer would be to swap out the suspected component for an identical model that is known to be good. If the problem stops, you know that it left in the unit that was just removed.
Since you have gone from one complete system to another totally different system, you have not started an isolation path that would narrow down your possibilities. Fortunately, your equipment is very likely fine. The fact that the problem occurred in the original factory head unit with a Jensen amp, and is still there after a total replacement of the active components in the system (everything but speakers are "active") indicates that neither the previous system nor the current one is at fault.
This eliminates one major path and it means the problem resides with either the installation or the vehicle. Since the vehicle is fairly new, there would be only a couple of possibilities. One would be an intrinsic problem in the vehicle, such as in mid '90s Chevy Cavaliers that have a faulty main harness behind the instrument cluster. Evidently, GM used a "wire stretcher" to get a little more length out of the harness (you can buy a wire stretcher at the same store that sells elbow grease, left-handed wrenches and skyhooks, if you know what I mean...). Installers would frequently get blamed for the vehicle going absolutely dead at random times. As the vehicle came back online, the whole dashboard lit up like a Christmas tree and the radio and clock would lose all settings. What effect would an alarm system or remote starter have on a radio and clock? Nothing. That is a standard symptom of having power totally interrupted. The Christmas tree effect is the "bulb check" function of the vehicle as the computer totally reboots. I suspect several shops paid huge repair bills to mechanics because they didn't follow this highly significant clue!