Charging alternater wire gets hot and archs

I usually try to check generator wiring circuits before replacing. You can see the fuses, not only check the fuses, use a test light or digital multimeter and check voltage on fuse circuits. As you can see, the two fuses on the left are hot all the time. The fuse on the right goes hot with key on. The generator needs excite voltage or it won't charge. The excite voltage usually comes through the charge indicator circuit.
The voltage regulator is usually inside generator, not external part. Just my opinion.

The wire from the alternator may be a fuse link or connect to one. Fuse links protect the wiring harness from going up in smoke when there is a high current short. Get a manual from an auto parts store to find the locations of the fuse links.

Check the wire from alternator to fuse box for a bad wire or a break in it. or corrosion on it. Battery cables loose or corroded. Is the battery ok!! check the main fuses in under hood fuse box. Good-Day! The charging wire goes to the fuse box first.

1998 trooper new alternator and still not charging and alternator bench tested good,
Check main 80 amp fuse in engine compartment and also check fuses in inside fuse box, there two in that one. first is engine fuse 15amp and the 10amp gauge fuse,

Here is the wiring diagram for the charging system as you asked for , also check connections, follow battery wire off the back of alternator make sure connections are good , that wire runs to engine fuse box and that is one fuse that i said to check it is 80amp, hope this is helpful good day

knowing the color codes can be a great help..usually in 12v reg system,from the regulator there are 6 white wire having a stripe codes,blue means neutral,green means field,black means ground to body,white means hot wired to +12v,yellow means to bat charging indicator going to instrument panel and finally red means to ignition....and always secure the regulators case to ground.

1) check 10A fuse in the batt. juction box (eng. comp.) hot at all times.
2) check the large red battery wire to the alt. for good conn.
3) make sure the alt. is grounded properly
4) gray wire sent from the alt. to the PCM
5) blue wire sent from the PCM to the regulator (alt.)
6) small red wire power frorm the 10A fuse
if all checks out and still not charge replace the alt.

the thiree wires usually are, one large heavy dity main wire that takes the charge current, one charge indicator wire and an exiter wire, when a car starts discharging it is usually one of the diodes in the alternator failed, there are usually 6 of these(at least) andthey should be dead short one way and open the other way when they fail they can be lowish resistance both ways and this discharges the battery, it will still show about 14 volts and give out 5/6ths of its rated amps but will drain, the ignition light(or charge light) is just a bulb from live to one diode and unless it is that diode that failed the lamp will work fine.The way to check is to measure the current through the alternator when the car is switched off, it should be very nearly zero

The ELD unit or Electrical Load Detector functions to monitor and regulate the output of the alternator. The ELD is located in the fuse box under the hood near the battery. It's a (typically) red rectangular box.
If the ELD unit is malfunctioning, it is very possible that it is preventing the alternator from putting out a charge. I do not know of a way to test it, other than to replace it.
Just to make sure, first check all battery connections, including the engine ground, for corrosion. All terminals and wires should be super clean, in order to rule out such a simple matter of a poor connection (this is very common). Also , make sure the power wires going into the fuse box and the ELD socket are free of corrosion.
I hope this helps. Good Luck!

Yes the White wire is the reason. It goes to the Internal Regulator.
As you view the connector that plugs into your alternator, look at where the lock tab is.
Lock tab on TOP. The Black wire goes to the Left side. The White wire goes to the Right side.

The Black wire, ties into the Red wire down in the wire loom. (The Red wire goes to the starter solenoid, and this is connected straight to the battery. This is why the Red, AND the Black wire, are both Hot wires)

The White wire goes through the bulkhead wire loom, and to the bulkhead connector.

(Down under the steering shaft, and on the firewall, you'll see a rectangular Black box shape, with a Bunch of wires, coming into it from the engine compartment. The bulkhead connector is two pieces. Following it through the firewall, the other side of it is the fuse panel)

Where the White wire connects in the fuse panel,
it should go straight to the ACC fuse. (Accessory)

When you touch the hot wire to the manifold you may have damaged your alternator. Take your Blazer to your local car service center such as Advance auto and have them run a test to make sure your rebuilt alternator is charging. Most centers will do this free of charge.