Allow me to add a few comments of value. The first has to do with the factory amplifier. All radios have a receiver section that picks out the station you want to listen to, and an amplifier that makes the signal loud enough so you can hear what the speakers reproduce. GM and Ford will often put that amplifier in a separate remote location. Without that amp, you'd be lucky to hear a very faint sound from the speakers when the volume was at maximum.
Some of their other models have the amplifier built into the radio. Everything works exactly the same way, but you have much less wiring to worry about. In short, when the original radio uses a remote-mounted amplifier, it MUST be used with that amplifier, and if it did not use a remote amplifier, it can not be used with one. To get technical for a moment, your speaker wires start out with 6 volts on them, then the amplifier runs them up as high as close to 12 volts, and as low as almost down to 0 volts, when at maximum volume. It can't go any further than that because the circuitry won't allow it to, and if you tried to, the signal would get cut off at 0 and 12 volts. You would hear that as extreme distortion. You wouldn't be able to stand to listen to that for more than few seconds.
Your new radio has an amplifier built into it already, AND, . . . if it has a pair of double wires with RCA plugs on the end, those come out before the amplifier. That means you can use the radio either way. What you can not do is run the new radio's speaker wires, which are already speaker-level output, through a second amplifier like you want to do, meaning the vehicle's original amp. Your radio's built-in amp is already driving the audio signal from 0 to 12 volts. The second amp would try to increase that to around more than 100 volts. Of course it can't really drive it to anything higher than the supply voltage, and that's where the really bad distortion comes in. Think of placing a step ladder on top of another step ladder. You're trying to get twice as high, but you're going to fall over before you achieve that. To feel stable, you're limited to one step ladder. To sound clear, you're limited to one amplifier, either the one built into the radio, or the remote amp, but not both.
At this point I need to add another comment for the people researching this topic. None of this wondrous information applies to Chrysler products. All Chrysler radios put out speaker-level output and will run speakers directly, AND they can be used with an additional remote amplifier or with the small amps built onto the speakers. All of those amps are only for tone conditioning for the shape of the vehicle. Chrysler amps do not increase power or volume. If you replace the factory radio with another one, at most you will need to turn the bass control way up or way down to sound right. Their higher-class Infinity radios put out less bass than normal, then it is made up in the amplifiers.
The orange wire you asked about is the "12 volt switched power" wire, but they call it something different to not confuse it with the "12-volt switched" coming from the ignition switch. It gets 12 volts switched onto it when the ignition switch is on, and the radio is turned on. That is the wire that tells the power antenna when to run up or down, AND it is the turn-on wire for a remote amplifier. This is not a power wire, as in powering your ear drum-blowing amplifier. That will have its own problems with getting enough current to function properly. That little orange wire will melt if you try to run anything on it. It is just a signal wire to tell other stuff when to turn on. Your truck's original amp has its own really fat ground wire, and a similar 12-volt feed wire that is always live. The amp turns on internally when that 12-volt signal comes in on the "turn-on" wire.
As has been mentioned already, you're better off using an adapter harness, but those are only going to take care of the two 12-volt power wires and the speaker wires. The truck's harness will have a tail light wire to tell the display to dim when you turn on the head lights, and a dash light wire to tell the display how much to dim. There will also be a pair of wires called the "data buss" for all the computers to talk back and forth to each other. The original radio used that for the speed-sensitive volume. Aftermarket radios don't use those so they won't be included in the adapter harness. Similarly, you car doesn't have a back-up camera, so there aren't going to be wires for that in the adapter harness. Those will have to have separate new wires run for those functions.
Getting back to the speakers, if your radio has those RCA cables, those are "line-level" output, which is too low to hear in a speaker. You should be able to run those to the original remote amp, but you'll have to connect the rear and front speakers together so the amp will power all of them. If your radio has four RCA cables, you should be able to use the front / rear fader function too.
For the generator whine, unplug the small plug on the rear / side of it. If the noise is gone, that is the source. If it is not gone, it's ignition system-related. As Steve W. mentioned, spark noise is being picked up by the antenna or by an antenna cable with poor shielding. That's the braided outer wire cover just under the first layer of insulation. It can also be picked up by the antenna if the base isn't making good contact with the fender sheet metal. If your antenna is a pair of fine black lines in the windshield, those often break leaving you with no antenna or a not much of one. All radios have circuitry that boosts its "gain" in an attempt to pull in a weak station. The drawback is when it has to work that hard, it also works that hard at finding sources of noise. That is a characteristic of AM radio. You won't hear most of that noise when you have a strong station tuned in.
You have one more serious issue to contend with. There is no way to sugar-coat it. GM went from having the world's second-best generator to by far the worst design ever, starting with the '87 model year. Due to their design, they develop huge voltage spikes that can destroy its internal diodes, its internal voltage regulator, interfere with computer sensor signals, AND send voltage pulses into the radio's power wires where it can show up as a loud whine. The original radios have an excessive amount of filtering to clean that up, otherwise they'd have a real lot of angry vehicle owners. The key component in damping and absorbing those harmful spikes is the battery. Do not do anything to degrade the connections between the battery's posts and the cable connected to them. A lot of people try to stuff new wires inside the cables, and clamp them in that way. We see that as starter problems when not enough current can get through, but even though the rest of the electrical system draws just a fraction as much current, the added resistance in the form of less-than-perfect connections impedes the battery's ability to dampen those spikes. I've seen people chase all kinds of elusive problems after adding their own make-shift wiring.
It is also real common for these generators to develop one failed internal diode of the six. That will reduce the generator's ability to produce its rated current to exactly one third of what it should be. 30 amps from the common 90-amp generator is not enough to run the entire electrical system under all conditions. The battery will have to make up the difference until it slowly runs down over days or weeks. These generators have a real high failure rate. It is not uncommon to go through four to six of them in the life of the vehicle. To reduce that number of repeat failures, when you need to replace the generator, always replace the battery at the same time, unless it is less than about two years old. It will work fine in an '86 or older model with the better generator. As the battery ages, the lead flakes off the plates, so there's less material to absorb those voltage spikes.
All AC generators develop three-phase output which is very efficient. There is always one phase coming up on producing its maximum output when the other two are going down. That results in a very smooth and steady voltage. Batteries like that. When one diode fails, one entire phase is lost. You'll get a pulse of voltage, (and current), a pulse of voltage, then a gap where voltage falls to perhaps as low as four to six volts. That is called "ripple" voltage, and in this sad story is extremely high. A good battery helps to smooth that out. That ripple voltage can be seen in the entire electrical system, including the two power wires for the radio. Imagine turning the radio on and off real fast, and what that would sound like. High ripple voltage is like doing that 1,000 times per second, and that is real easy to hear as a whine in the speakers. It will increase in frequency, (pitch), when you speed up the engine.
Noise radiating in from the ignition system is not affected as much by engine speed. With generators, you're getting a steady series of pulses that increase in number when the engine speed increases. More pulses per second means higher pitch. With spark noise, it's true you do get more pulses per second when you increase engine speed, but with that system, you get a pulse, then a gap, more gap, . . . wait for it, . . . still more gap, then finally another pulse. Think of this as a single pulse of real low frequency, then you just get more of those single pulses when engine speed increases. Usually you'll hear spark noise as a low-pitched growl that only gets louder when engine speed goes up, not higher in pitch.
For my final comment of value, a lot of people ask about installing a larger generator to power add-on equipment. That is possible when there were multiple optional sizes for your application, either when the truck was built, or if one became available years later, but there are some things to consider. In the past, as in the '70s and '80s, there could have been a 45-amp generator as standard equipment, a 60-amp if the vehicle had options that required it, and even an 80-amp for police vehicles. My '80 Volare has $500.00 worth of factory-added plastic trim panels, and an AM / FM radio. That warranted a bigger alternator. (Alternator and AC generator are the same thing. To use correct terminology, Chrysler copyrighted the term "alternator", but everyone will know what you mean when you use that term). The output wire going back to the battery is large enough to carry the maximum current any available generator can produce. As a related point of great interest, AC generators are physically incapable of developing more current than they are designed for. No matter which generator you upgrade to, the output wire can handle it. Where the problem comes in is there is a fuse in that wire. AC generators have two sets of three diodes, six in total, at a minimum. If one shorts in each set, you'll have a direct short from the battery's positive post to ground, and a real lot of smoke and excitement. On those older cars, the fuse was in the form of a fuse link wire spliced into the output wire, usually near the battery. While the output wire is large enough to handle any generator, the fuse link is not. Its size is selected at the factory based on the size of the generator being installed. The other point you need to understand is the generator will only develop the amount of current the electrical system needs at that instant, and no more. If you have a 90-amp generator, and the electrical system needs 37 amps, it is going to develop exactly 37 amps, regardless of engine speed. If you install a 120-amp generator, and the system still needs 37 amps, you are still only going to get 37 amps. Think of your air compressor. If your tool is drawing one cubic foot of air per minute, that's all the air that's going to flow through the hose, even though the compressor has the capability of producing more. If you switch to a larger compressor, that tool is still only going to draw one cubic foot per minute.
Where this great and exciting story becomes important is while it's true you won't get more current simply by installing a larger generator, you WILL reach its maximum current during an output current load test. Along with ripple voltage and charging system voltage, the full-load output current test shows if the generator can develop its rated maximum current, one third of that value due to a failed diode, or 0 amps due to some other defect. That test requires a professional load tester, and it only takes a few seconds; just enough time to read the display. The problem is that fuse link wire. Up to now you had the capability to produce a higher amount of current, but that never actually happened because the electrical system didn't need it. If you had installed a larger generator, NOW is when that higher current will be produced during that brief full-load test. On the older cars with fuse link wires, those take some time to burn open, just like delayed-action fuses in your house, for motors. Fuse links are simply a short section of smaller diameter wire that makes it the weak link in the chain. The secret though is their insulation is designed to not burn or melt. You buy replacement pieces by the insulation's color to denote its current rating. Due to its delayed action, they usually survive that short burst of high current during the full-load output current test, as long as it only takes a few seconds. With a truck as new as yours, you are more likely to have a regular fuse bolted into the under-hood fuse box. Those do not have the time delay characteristic. That fuse size is selected at the factory based on the size of the generator that was installed there. You won't have a problem as long as no one performs the full-load output test, . . . or you don't add something that draws a ridiculous amount of current, (amplifier loud enough to entertain the entire neighborhood).
When the generator is upgraded to one with a higher current capacity, we needed to replace the fuse link wire with one appropriate for that unit. Fortunately those were listed in the wiring diagrams, so it was easy to know which size to get. The problem now is it isn't always as simple as bolting in a larger fuse. Cost of material is such a big concern that they typically don't put in an output wire that can handle any generator. If your truck came with a 90-amp generator, the output wire is just large enough to handle around 100 amps, but not for very long. If the truck came with a 120-amp generator, it would have come with a slightly larger output wire. If that bigger wire wasn't needed, you would have gotten the smaller wire to save on cost. Now you have a problem when upgrading to a larger generator. The irritating thumps from your amplifier draw a real big pulse of current; much more than when playing the high notes at the same volume. If you don't upgrade the output wire to a larger size, the current will still get through, and since the pulses are intermittent, the wire likely won't overheat, but it's a sad fact that all wire has some resistance in it, just like every hose and water pipe has some resistance in it. If they didn't, opening a fire hydrant would cause the municipal water tower to empty instantly. In reality, the resistance in the pipes results in the water pressure in the hose being a lot lower than the pressure in the tower. Voltage is electrical pressure. When there's resistance in the output wire, it limits the free flow of current in that wire. Using a large diameter wire makes its resistance too low to be noticeable in that circuit. But when you add more loads, (amplifier), that high current causes some voltage, (pressure), to be dropped across that wire. The generator might be putting out 14.5 volts, but after going through all that wire, you might end up with 13.0 volts at the amp. The bigger problem is since the current flow is pulsing in time with the "music", the voltage at the amp is also pulsing up and down. That shows up as distortion. As the supply voltage pulses up and down, so does the volume. (Sure took a long time to get to that explanation). Some people will add large capacitors to smooth out those voltage fluctuations, but to be effective, they have to be right next to the amp, not up front by the generator. This would be similar to adding a small water storage tank to a pump in a well. That tank allows the pulses of current, (water flow), to occur while maintaining a smooth, steady pressure in the rest of the system.
Too many people think loud is the final goal, and everyone will appreciate the music, but they forget about clean, crisp, clear sound that is pleasing to listen to. Achieving that requires eliminating all those sources of distortion.
Sep 14, 2017 at 1:06 AM
