Truck not charging, electrical weakling seeking advice

[99Runnr]

I will keep this initial portion blunt. My truck was discharging the battery out of nowhere this weekend. 11.8v at idle, 11.8v with it off. Checked alternator an it passed, 3 times consecutive. Truck is still not charging.

-Checked ALL fuses, except main (150A?) alt fuse
-Only one light on dash, driver airbag light
-Signals not working on lever, but flash with hazards like normal
-Heater display is blank. It lights up, but no function/time/mpg display
-Ground is solid, no corrosion, cleaned all connections, tightened terminal
-Power is solid, just re-did all connections, no corrosion, wire is solid with no splices or damage.

Thoughts? Has anyone had this linked issue before? Google returned a few VERY similar symptoms, but each of them brought no follow up.

THOROUGH VERSION HERE;

Friday night I swapped head units. Kenwood for Kenwood dual din. Same harness, unplug and plugged in main harness, antenna, RCA's, ONLY thing different was a tap into power an ground on harness for backup camera. Installed, checked power WITH THE HEATER CONTROL unplugged. I suspected airbag light as a consequence. Said shit, put it together, started it, no lights period. Tuned new head unit, took it for a drive, all good, camera performs flawless.

Saturday morning I am going shooting, I get up, go get gas, then to Walmart for a pass, then to Cabelas for ammo, ect. I make 5 start and shut off cycles, no lights, nothing abnormal. 6th cycle we are leaving to shoot. 21 miles from home, I get the airbag light ONLY. I am not real shocked, an continue on. 5ish minutes later, the check engine light, VSC, traction control, e-brake light, ALL that crap comes on, but no battery light. I pull over an shut the truck off, everything working as normal. Windows, signals, radio, has power, ect. I look an see if anything catastrophic just happened, go to start the truck again and I get starter click click click. Go over wiring, another once over, check terminals, all seems fine. Start it, fires right up, slight hesitation after initial fire an idle stabilized after maybe 1 second but I noticed it. Start heading home, truck abruptly dies, no dimming of lights, no power loss, I was accelerating uphill prior for a good 1/2 mile, I'd have felt it. I let off at the top an dead.

Pull over, this time it never fired again. I am in the middle of nowhere essentially, after 5 hours no tow trucks will come, I finally get someone to rescue an bring a new battery an OBD reader if nothing else. Battery get's it going, ONE light remains only, the air bag light. All functions perform, signals, radio, power, traction control again. I drive the 30 minute trip home, check an 11.8v at idle and off with the brand new battery, signals stopped working, no heater control, no display for mpg, no new dash lights. Both batteries now, original and brand new read 11.8v. The new one just got me home.

So, test alternator, passes. Inspected wiring, checked all fuses except the main one under the fuse box, look for anything off, an here I am. Suggestions? Idiot proof test theories? I am very poor at electrical diagnostics. I learned to install stereo's proficiently and haven't ever gone much further. It's my least favorite an depth ability with mechanics, otherwise I can build about anything but never dabbled in electrical. So please consider that if there is something stupid I'm missing here.

 

[djkurious]

In my experience to start troubleshooting I would disconnect the radio you just recently installed to isolate the issue and start from there. Also in my past experiences I have seen alternators go bad because of the bad diodes or voltage regulators but still past a test.

 

[99Runnr]

In my experience to start troubleshooting I would disconnect the radio you just recently installed to isolate the issue and start from there. Also in my past experiences I have seen alternators go bad because of the bad diodes or voltage regulators but still past a test.

Thanks for the input. I can pull the radio fuse, but if I wired something wrong enough to cause alternator issue, wouldn't it have popped the little 15A radio fuse first? I went over my wiring once again, nothing out of place. I tried to point the finger at what I did as well, an the other functioning aspects seemed to verify it wasn't that.

An as far as the alternator goes, I can just order and replace this with a new Denso unit. However, I would like to learn from this rather then assume if I can. Is there anything else I can do to simply verify where the missing link? Like I said, I'm assuming there is something simple that I have never tampered with I can do to test things and narrow it down.

 

[99Runnr]

Ok.. looked at 140A fuse for alt. Looks fine, not blown.

Went over wiring for the 10th time. No corrosion, no breaks, no fuses gone anywhere in the truck, interior, exterior, even swapped the 7.5A alternator fuse out for another brand new 7.5. Checked all ECU fuses, all fuses related to what isn't functioning.

I'm starting to lean on the test for alternator was faulty. No clue what else this could be. My multi-meter just broke as well. So I'm getting another one plus an OBD reader, as my BATTERY light does not work, I assumed it would pop up on accessory for a second and shut off like the other warning gauges? It does not show whatsoever, so if it's burnt out, I will see a code still lingering I'm assuming.

Still feel like someone has had this happen an can give me valuable information. If I can't find anything by morning I'm next day airing a new Denso alternator in from RockAuto either way. Don't care about the money for parts, it's all got 160k an doesn't bother me to replace, so if that works, great.

 

[99Runnr]

Update if anyone else runs into this, I did some more digging.

Truck running, I was @ 12.18 volt's after charging up the battery. I had a fluctuation of 9.6-12.03v at the alternator post. Seemed to be a faulty regulator. Replaced alternator with a new unit, fluctuation is GONE but alternator is a dead steady 11.98v now.

Did some testing at the regulator plug, 12.12v with ignition on. It's now narrowed down to the voltage wire with the fusible links. Apparently I'm getting high resistance through that wire as it only had 11.14v. I have no diagram's here, just know a few people with Alldata who have asked me to test things. Best I have followed where things get grey for me, friend is coming Thursday to put hands on it himself (plus he said we'd need 2 people for testing beyond where I'm at).

The code for the airbag light comes in as; B1152 OFF Indicator Open, Driving Circuit. I cleared the code and it immediately popped back up as a recent code and current code.

Any wiring guru's out there? This marks 6 days without a truck for me. I'm not solid with wiring whatsoever, but never been defeated like this before with an issue out of nowhere. Maybe someone had the same thing happened an can save me the hassle here. Never ONCE had a Toyota give me hell through wiring like this.

 

[Drunner97]

What's your idle at when you're checking? Have you let the ECU relearn the idle yet from the battery being dead/disconnected. I believe you have to be over 650 rpms before it actually begins charging. I banged my head against the wall for a few weeks trying to figure it out myself a couple years ago. Best thing to do is make sure the battery is fully charged (at least 12.6-12.7) reset the ECU, and then let it idle for 5-10 mins. It should fix the idle.

 

[99Runnr]

What's your idle at when you're checking? Have you let the ECU relearn the idle yet from the battery being dead/disconnected. I believe you have to be over 650 rpms before it actually begins charging. I banged my head against the wall for a few weeks trying to figure it out myself a couple years ago. Best thing to do is make sure the battery is fully charged (at least 12.6-12.7) reset the ECU, and then let it idle for 5-10 mins. It should fix the idle.

I actually used an OBD reader and it had me hold the idle at 2000 RPM for 20 seconds. It does an electrical system test, this is where it registered 12.1x volt's, didn't increase with RPM whatsoever an it gave me the super helpful info; have a professional inspect truck.

It is idling over 650. It idled for at least 5 minutes when I did all my voltage tests and so forth, no change, no voltage increase right off the alternator post when running (as I said, new alt is no longer having voltage surge but it's not even putting out 12v).

Totally exhausted by this.