To solder if you have one of those small soldering irons. Connect and flux the wires you want to solder. Get the soldering iron hot, dip it into the flux and melt some solder onto it. Solder the wires by touching them with the hot iron and allowing the solder that is melted on it to flow onto them, you can dip solder from a roll of electrical solder as you do this. The solder I have is thin almost as thin as a sewing needle. I think it came with the soldering iron I have which is good for nothing but wires. OH yea avoid the fumes.
Tangent-Anyone know where to get a good heavy soldering iron?

 

Is it corrosion? Or is the wire burnt? I have seen wires wick moisture down them, so you get corroded copper for quite a distance..... I have also seen wires that were burning on the inside (literally) but, the insulation isn't damaged......

 

It could be corrosion HY. Didn't think of that. Not sure how it would get corroded in that spot in 1-1/2 years but I'll believe anything at this point. Gets pretty humid under that hood I suspect. Maybe that's why those alternators come with that funky rubber retainer around the terminals (I took mine off when I installed the external regulator). When I went to rework the connection, the wires were discolored...not bright and shiny but rather a dark grey. Additionally, they crumbled into short pieces and fell off. I didn't have much slack so not much extra wire to work with. I cut it back as far as I could. The wire was still dark and a bit brittle but it wasn't crumbling as bad. It was good enough for me to crimp a ring terminal on and reconnect it. Seemed to work but not for long. There is some intermittency to this problem. The gauge dances at idle most of the time but there are times it's steady as a rock. Always steady while I'm driving.

When I reconnect it I'll get some heat shrink and dielectric grease around those connections on the alternator. I'm beginning to think your corrosion theory has merit.

 

Someone needs to take my soldering iron away from me. I never could solder well. I'm not convinced it's the best connection for most automotive applications anyway. I do well soldering two ends together but for some reason I suck at terminals. Lol

 

That sounds like corrosion. Not a surprise. It happens.

For soldering, the trick is to get the wire, and the connector, fairly hot, and let the solder flow into both.

 

Touche' !! Shaky gauge and flickering lights fixed.

Went back about 10" on both field wires and spliced in new wire using butt connectors. Nice clean strands back there. Crimped new ring terminals on the end. Heat shrunk it all. Tested continuity. Hooked it up. Steady Eddy!

I was thinking burnt wires, HY was thinking corroded wires. HY for the win. Good call HY!

Thanks for the help. Let's hope it stays fixed.

I can hear Ralph from his grave. "Check the connections! Check the connections! Check the connections!" LOL. Rest in peace, Friend.

 

Indeed. He may be gone from this forum, and this world, but, his spirit is going to live on here for quite some time.

 

I don't know what to think anymore. Just when I believe I can actually drive my truck for a week with no problems. Not meant to be.

Went to pick up a pizza last night. My dash voltage gauge was dancing again.

Quick Recap
Spring, 2020: Installed reman PCM (micro processor on original PCM was wigging out). Discovered voltage regulator did not work. Per a suggestion by Hey You, I decided to keep the PCM and install an external voltage regulator to bypass the failed regulator in the reman PCM. After some piddling around I finally got it right and everything worked great.

Fall, 2021: Noticed voltage gauge dancing around.

1/1/2022: Finally got around to looking at the dancing voltage gauge and discovered the connection to the alternator was bad. In fact, both field wires came off above the ring terminals. Trimmed the end of the wires and put new connectors on and reattached to the alternator. Problem solved. Gauge as steady as a rock.

2/2/2022: Voltage gauge started dancing around again. Realized the wires near the alternator had corroded and I didn't trim enough wire off on 1/1/2022 (I didn't have a long enuf wire to trim off more). So I went back a good 12" and crimped in new splices with new wire on both field wires, added new ring terminals and reconnected it to the alternator. Problem solved. Gauge steady as a rock.

3/26/2022: Gauge dancing around again when I went to pick up the pizza.

3/27/2022: Was going to make another new connection at the alternator this morning just to see if it was the same problem. Decided to fire up the truck before I made the new connection and saw the gauge was steady as a rock again. Drove it a few miles and the gauge remained steady. My truck fixed itself. I'm wary of when my truck fixes itself and expect the gauge to start dancing around again.

I know...check ground connections, check all connections. I hear you Ralph! I've been over these connections one million times. I don't know how many more times I can recheck before I wear out the connections and cause more problems. I'll wait to see if this was a one off but I wont be holding my breath. That external voltage regulator is tops on my suspect list but that doesn't mean it's the problem. Maybe my reman PCM had a brain fart but the wires from the PCM to the alternator are not even hooked up so I don't know what to think anymore. Any thoughts?

UPDATE: Took truck out this afternoon. Gauge is back to dancing around again. Quite erratic. Would seem fine for awhile, then dance violently for a bit, then back n firth. Always at idle. Re-did the connections on the two alternator wires...made no difference. The connectors I had looked good. Officially out of ideas.

 

When the gauge is doing its dance, but a meter on the alternator output, and see what it is actually doing. Might be a bad connection on the back of the cluster.....

 

I had Advanced Auto hook up their fancy scope a month or two back and the results came back with flying colors. The alternator graph line was tight, near flat. Very little fluctuation at idle and 2000 RPM. Battery was like new (because it was new), and the starter came back strong. But I will throw the multimeter on again to see what I get. I remember Ralph telling me a digital meter will not necessarily pick up the fluctuations, A scope would be the best method to look for that, hence why I had Advanced do it. I'm gonna try a few other things too like checking ground viability where I have the regulator grounded, check the regulator ohms, make sure my tensioner is working, might adjust that regulator too. Have it set at 14.0ish volts. Maybe if I bump it to 14.2ish... That adjustable regulator doesn't give me lots of confidence but I know how to check it off the truck.

When you say "cluster" I assume you mean behind the dash? I'm not an electronics guy so you have to speak like you're talking to an idiot because that's what I am when it comes to electronics. I happened to find a guy on You Tube who replaced his temp/oil gauge on his '88 Dakota. Looks pretty simple to get to those gauges (getting behind it not sure about). I never had my dash panels off. If it gets to that point I may need you to look at this short 3 minute video and give me a pointer or two. Looks like an idiot can cause a lot of problems digging into that dash and I don't want to be an idiot.

Thanks HY.

UPDATE: Went back and made new field wire splices. Soldered them this time. New ring terminals again. Dialelectric grease and heat shrink. Went back and cleaned the ground going to the regulator. Got some healthy connections. I also pulled the regulator and did an "AlternatorMan" check (see video below). He is who I bought the regulator from. I put it at 1.75 ohms like he did but when I checked the alternator output it was 14.9v. Too high!. Backed the ohms up to 1.80 and the output was 14.4v. Backed up the ohms a touch again (about 1.82) and the output is sitting at 14.10v on the money. That's exactly 0.10v more than what it had been before I started messing with it. Anyway. The gauge danced all around when it was at 14.8 and 14.4. It stopped dancing after I set it to 14.1v. But I'm far from calling this fixed. Sometimes that gauge is steady. It doesn't always dance around. So I'll keep an eye and see what happens.

Notice AlternatorMan adjusts his (I have exact same regulator) to 1.75 ohms and he claims that yields 14.3v. Uh, mine yielded 14.9v at 1.75 ohms. Not close. And yet another reason why I don't have the utmost confidence in that regulator.

I welcome your thoughts, HY.