Charging System Issue

I have a 1999 Tacoma 3.4L and recently when I first start the truck up in the morning the battery light would turn on. After it would be on for a few minutes or I would drive it about 100ft the light would turn off. First thing I did was replace the battery since it was old and nearing the end of its life, that didn't really change things so I had autozone test the alternator and they said it was bad. So I replaced it today and took it back to autozone and had them test it again just to see and it still says I have an issue with my charging system. I've read thing about checking fuses and it may be a grounding issue but I'm not even sure where to begin, I was really hoping that would solve the issue and I wouldn't need to track down all the wiring. Any advice or help would be greatly appreciated.

 

The connector on the starter fixed mine.

 

Hmmm
So you replaced battery and alternator
This batt light still comes on and goes off as you describe?

 

The connector on the starter fixed mine.

 

What exactly did you do to fix that?

 

Yeah, and the battery tester they use at AutoZone says there's an issue with the charging system.

 

Well, in layman’s terms….the alt IS the charging system.

would start there
I mean, trace the wires/harness from back of alternator
See where they go
Inspect for ‘weirdness’ like cut/pinched wires or loose bolts or loose pigtails

I RR’d both battery/alt on another vehicle that just had short block installed
Same results as you
I traced one loom from alternator to fuse box…..flipped over the fuse box and the loom’s pigtail seemed loose. I pressed hard and heard a ‘click’
Solved
Appeared pigtail wasn’t fully seated after engine installed

keep us posted!

 

I just cleaned the connections. The connectors need replacing on mine. Alternator charges battery after cleaning contacts on starter.. I just unplugged it then poked around at it with something and blew it clean. I have new battery and alternator also. I will rebuild original alternator when i get parts.

 

Ok for sure, that'll be the next thing I check out. I will post the results.

 

I have some electronics cleaner so maybe I'll spray all of the plugs with that and see what happens.

 

Awesome
Looks like fixmytaco did same thing found ‘weirdness’ with wires going to starter

 

when u spray/clean
Inspect too
Only bc I have done this few times ….
Jammed pigtail together and bent a pin
That would not make contact bc of my sloppy work
Simple fix bend back into place

 

I couldn't really see too much because it's night time and the flashlight wasn't helping much lol, I'll have to inspect more in the daylight. But the pigtail plug that goes into the alternator had what looked like dried up dielectric grease so maybe that had a part to play in it. I cleaned that all out with the spray cleaner and cleaned out the pigtail that goes into the fusebox as well. So hopefully that does something, I'll find out tomorrow, if not then I'll probably have to start inspecting the wiring.

 

My Lexus LS430 smoked the alternator the first night I owned it. Left me stranded. I could smell the burning when it failed. I did a big 3 upgrade for the large power and ground wires.

Battery + to alternator and to starter. 4 GA wire for ground too. Ground upgrades from Battery to frame, battery to engine block. Never had an issue again. I highly recommend adding wiring. Might not have to remove your current wiring, if you don't have to. Electricity will take the path of least resistance.

 

Yeah upgrading the wiring is something I'm definitely going to have to do at some point, I'm tight on money currently especially after the new alternator but looking how things are right now the wiring is something I'm going to have to do soon whether I want to or not.

 

I made my own wiring. Bought the proper terminals from Amazon. 4 GA red and black wire from O'Reilly auto. Got a large terminal crimper as well. It was cheaper than buying a kit.

 

Update: I remembered that I had some thick wiring laying around that I had taken home from work, hooked it up from the positive lead on the alternator to the positive lead on the battery and took it back to autozone and had them test it. The test came back that the charging system was good so that must have been the issue. Now I just need to figure out the gauge of the wires I have so I can install the necessary hardware. I think they're 1GA but they may be bigger, I'll attach photos below.

 

I was going to use that trick if the starter connection was working okay. Had some 10gauge jumper wire ready and a fuse.

 

Hmm
Unk if that scavenged wire was like that b4 u mounted…….

that ‘flat’ melted section
That is good place for current to escape

 

Yeah it was more of a test to see if that would work for me, I ended up replacing it with some 4ga wire and it stopped working again so I went back to that wire and put some heat shrink around that part but it is still no longer working so I'm back at square one now.