ABS, Brake, Engine, and Battery voltage lights on?

Let me start by saying I apologize if this is in the wrong section, and hopefully it's able to be moved to where it belongs without much hassle. As you can probably tell, I'm new to this forum, so I'm not too sure as far as posting and considering the time at the moment, I don't have the time to read through everything. So again, I'm sorry if this is in the wrong place..

On to my issue..

We purchased a used 2003 Dodge Ram 1500, 5.7L Hemi just the other day. When I test drove it (I drove it twice before buying, and the person that owned it prior was using it between times) there were no issues, no lights on, etc. Bringing it over the mountain to our place, the dash turned into a Christmas tree. ABS, Brake, Engine are all solid lights. Battery light was blinking as well, so I checked around and found that a bad battery can make the dash lights go wonky in several Dodge models, so I replaced it. The battery was horrible, as if it's never been changed, so I'm very glad to have done it (even though it took some doing to make it run and idle properly afterward).

Long story short, the ABS and brake lights started coming on and going off intermittently within a few miles of driving. Check engine light came back on tonight on the way back home as well; now the brake and ABS stay solid when they come on and the battery light is also flashing again. I've read around and found that people have issues with the magnetic speed sensors, but I have no speedometer issues at all. It doesn't idle funny anymore (other than after changing the battery, but I've read that's just a Dodge quirk, so I don't know), and it has no issues with stopping, sitting idle, etc. I'm unsure what's going on. I've had a code reader pull codes prior to installing the battery and the codes were for the following:

Front (left and right) ABS circuit malfunction
Engine light was determined to be exhaust leakage, cat, or just a bad batch of gas
And a code for Bank 1, Sensor 2 low voltage O2 sensor.

As I've only driven the truck less than 2 days, I've yet to determine if the engine light is the result of bad gas, but it doesn't run as if the converter is clogged, and there's no exhaust leaks anywhere that I can see, feel, or hear. I've crawled the entire length of the truck looking for exhaust leaks and broken lineage, hoses, etc in case any of the codes were indicative of a wiring issue. I've found nothing in the open that I can see or feel.

My question is, is there anything specific to the model year (or years) that could be causing the brake lights to both illuminate (as a separate issue) and what would cause both the voltage light to blink, as well as a check engine light to illuminate together? It's as if these are definitely two separate issues, though I don't know. But the two sets of lights almost always come on together. The oddest part of all of this is, when braking coming down off the mountain is when the lights seem to all decide they need to be on, so I'm curious to get some feedback as to what on earth is happening with this truck. Please keep in mind that I don't have any speedometer issues, so I don't believe there's actually a severe problem with the ABS speed sensors (as far as the magnetic issues are concerned, anyway.)

I apologize for the very long post, but I hope I can get some feedback as soon as possible. I intend to do some more looking over things tomorrow. I might end up lifting it up to have a better look around. Any feedback or help would be greatly appreciated. Thanks in advance!

Did you check the alt. output or just throw a battery at it?
Low voltage will result in all kinds of weird **** including turning lots of lights on.

I've not checked the alternator output, no. I threw a new battery into it, because the negative terminal post was literally welding itself to the connection. I used the on/off cycle to determine what the actual codes are and got several.

P0137 - O2 sensor shorted to ground
P0138 - O2 sensor shorted to voltage
P0440 - EVAP performance
P0579 - Cruise Control malfunction - Input A Circuit Stuck (Cruise does not work)
P2106 - Throttle actuator Control system - Forced Limited Power
P2175 - Throttle Actuator Control System - Low Airflow


I walked out to the truck to start combing wiring and noticed something today - While the truck sits parked, it randomly makes a buzzing noise as if something is exposed and grounding itself out. It sounds like a "burrrp" that barely lasts one second, almost like a cell phone vibrating against a table, but softer (no, the phone isn't vibrating lol)

I'm currently intent to check to see if there's any nesting or anything in the truck, due to it sitting for quite a while prior to purchase, that could be causing the airflow issues. No idea why the cruise doesn't work, aside from the code, and no idea if the other codes are the result of an alternator issue, a dead O2 sensor, or just something stupid happening with the wiring.

EDIT:
The alternator has actually been replaced in the truck prior to our purchasing it. I'm not sure when, but it's very clearly a newer one. [strike]Upon fixing some loose wiring connections, I reset the PCM by pulling the fuse.Doing this resulted in the truck acting the same as it did after changing the battery. Idles itself out and turns off, unless the throttle is slightly pressed. I have it back to idling somewhat smoothly, but I'm curious if this is meant to keep happening, or if there's something faulty somewhere.[/strike] The red, striked out text was a direct result of a filthy throttle body. After it was cleaned, all of these issues disappeared entirely. The truck now idles smoothly and has no issues starting up with a single crank.

EDIT2: I've removed and cleaned the throttle body as suggested in other posts. No problems starting the truck and sluggish idle has completely vanished, even after PCM resets. All codes are gone (for the moment, but hopefully they stay away). Cruise control now works properly (very odd, but I'd assume it was due to the truck being in Limited Power mode). No ABS problems, which usually recur directly after a short drive. I've gone over some of the wiring and have yet to find any problems with it.

Just as a side note - Does anyone happen to know where I can find a complete wiring diagram for the 2003 Hemi 1500? I only ask because it's much less a challenge to chase wiring with a diagram than trying to find them all. It'd be greatly appreciated if anyone could provide them. If someone's got a subscription to Haynes online manual for this truck, print screens would work perfectly for the wiring diagrams, if it's not too much hassle (unless they can be found somewhere else!)