Electrical whine and popping

Hi, I am looking for assistance in diagnosing a couple of issues. a loud whine when the car is running and a popping sound. I can provide my observations and hopefully someone can help guide me through further process of elimination. Currently i have a Pioneer HU, one 4-channel amp,, dist block, and crossovers for the front component speakers

- With the car started, there is a loud whine which s constant, with the car in accessory mode, the whine is not present.
- When using the power windows, the whine is presented loudest. When accelerating, the whine increases.
- loud popping sound when going from volume level 0 to 1 and 1 to 0, also and when changing radio stations (in accessory mode) Also when turning on / off the car
- no popping sounds when increasing volume or leaving radio playing (in accessory mode)
- I tried using different sets of RCA cables on the rear speakers alone, then the front speakers alone. The popping continued in each scenario. (accessory mode)
- I removed each speaker wire from the amp, one by one, the popping continued.
- distribution block lost it's ability to show the voltage, perhaps some clue or maybe irrelevant. Fuses are not broken and it is grounded. Amp powers on fine.

Can anyone make sense of this or help guide me to next steps to troubleshoot further. With the whine with the power windows, i'm thinking a power wire is touching metal somewhere? I'm overwhelmed, please help

The whine is most likely alternator whine. you should look up ways to "cure alternator whine" One that I used many years ago was to ground the shield of the RCA to the back of the radio. YMMV. That was in my old S-10 Blazer with a Clarion CD player.
Which model of Pioneer radio? A possibility is that your radio has picofuses in it. These could be blown and from reading I believe they get blown by hot swapping rca wires. Even if you have never done this these picofuses could still be blown. I am not personally aware of a way that these can be repaired.
Which model of amp?

Make sure none of your speaker wires are touching anything metal in the car. a stray wire touch ground causes terrible problems that can manifest intermittently and be very frustrating. if you have old factory speaker wires that are hot because they were hooked to your HU wiring before you added the amp those could be a culprit. I had that issue personally. Even though all my speakers were run off a separate amp the factory wires were hooked to the HU amp and were hot. They touched metal sometimes if you closed the car door and oh boy it was terrible.

Is there a way you can hook up a different HU to test? In a separate test could you hook up a different amp? This way you could isolate if it's the HU, the amp, or something in the car independent of either of these.

This is a long process but I think if you logically go through your set up and isolate each piece you will be able to pinpoint the issue and resolve it.

The easiest would be to unplug the RCAs from the amp and see if the noise continues. If it goes away, then you know the issue is farther forward...but if it continues, it could be the amp, or some grounding issue.
If, after unplugging it, the noise goes away, reconnect the RCA to the amp, and unplug it from the radio. If the noise continues, it's a bad cable. If it goes away, it's radio-related.

I once had a frustrating experience trying to track down a popping noise that occurred when I powered off my stereo. I initially thought it was a grounding problem, but after trying different grounding connections and RCA cables, I realized the source was my headrest monitors. The monitors were being activated by the remote turn-on signal from my main unit, which was causing the popping noise. I was able to fix the problem by disconnecting the remote turn-on signal from the monitors.