No crank, no lights, help!

Possibly, but why would the headlights work, but not the lights on the dash?

 

Although that could be true, why is it when I put a battery charger directly onto the terminals, it doesn’t fix it. Wouldn’t doing that eliminate the battery being the problem?

 

Since we're not doing the diagnostics, there's all kinds of Qs we can't answer.

But when one drives multiple days with a failing alternator and the vehicle won't start, start simple. Test the highly likely ruined ( or at least dead) battery first.

A good battery will start a vehicle with a dead alternator. It just won't stay charged.

When a known good battery is in place, the true diagnostics can start.

Side bar. Both battery and alternator can futz with ECUs since they are voltage picky. Hopefully it's not one of them damaged.

 

My questions this far to OP have been for my diagnostics.
Kind of like how I’d go about diagnosing it.



For anyone interested, here is my “flow chart” of diagnoses.
I’ve got to run out for a bit, I’ll jump back on in an hour.
Until then, we need to know why(if) we don’t have power from the AM1 fuse.
It powers A LOT of different stuff. The IG1 and IG 2 being the big ones.
Again, I’m still trying to to verify where we do and don’t have power.

 

Maybe, but not always. They aren't made to substitute, they are made to recharge or give some boost. Seeing voltage you like doesn't reflect the available amps.

If I'm wrong, you're out nothing but some effort. And you won't be any worse off than you are now.

 

FWIW, this is the charging system circuit.
Take a look at what’s involved?
See any commons?

 

Ok. So basically right now, I’m gonna try to rule out the battery, to get it out of they way. Then I’m going to see if I’m getting power to or from the AM1 fuse.
I work on cars a lot but unfortunately I’m so unfamiliar with anything electrical related, so thank you for all this help.

 

I’m not trying to put you down OP, but it would be nice if you knew more about diagnosing electrical issues. Based off your description of testing the “big wire”. This isn’t going to be easy for you. But I’ll do my best to help.

Here are the steps I’d take to diagnose your issue.
1. Battery voltage while cranking
2. Voltage at the STA fuse when cranking
3. Voltage to the WIP fuse key ON position
4. Key on and off check power to 7.5A Gauge fuse.

 

Put your meter on the battery. See if it’s 12.4v or more

Next,
Red lead to battery +
Black to battery -
Try to crank the engine, see if battery voltage falls below 9.75v.

Battery checked

 

Haha. Thank you for you patience

The voltage while cranking didn’t drop at all. Stayed at 12.8 the whole time…

 

Good enough for me to say, “It ain’t the battery”.
But then again, I never thought it was the battery.

See post #28.
Do those checks. We will continue after you post your results.

 

I’ll be able to do this tomorrow. I’ll update you as soon as I’m done.

 

I’m seeing some red flags.

When you say this

When you say this too, not trying to be mean but you need someone to help you.

Guessing this is a battery charger with a jump start feature. If it cranks with this charger, it’s probably ok. Still the better way is to use another car and jumper cables.

This is an awful high starter voltage drop test result. If your meter has a peak high peak low feature, set it for peak low and retest.

If you’ve given up for the day, hook up your charger set to trickle charge, or the lowest setting and leave it charging overnight. It should be fully charged tomorrow and ready to continue troubleshooting.

If necessary, get someone to help you test the fuses suggested.

Was the other alternator making noise? Belt squeeling? Engine labored or bogging? Are the battery terminals and posts covered with acid? Posts clean and silver or black and oxidized?

I’ve seen alternators fail and stop charging. Lights go dim, rpm’s drop, eventually it stalls. Or occasionally fail and overcharge. Lights might seem brighter, you might hear and smell the belt slipping, you’ll probably smell the battery cooking.

 

The truck doesn’t even crank.
The test was just to rule out a “really bad” battery.

 

Some good troubleshooting tip so far but according to his profile the OP has an 02 so the diagrams posted are not correct.
I don't have OE diagrams for 02 but here's the one for 2000, it should be the same.

There are no modules involved in the starting circuit, a failed PCM could cause a no start but it will not cause a no crank.

 

Well that’s not funny, but it kind of is.
FWIW, I still don’t think it is the battery.

 

2002 Starting

 

I feel this has gone a little off course a bit, and we are just discussing my lack of skills now. I maybe didn’t explain it well in the first place.

I feel very strongly that it is not the battery. After I first discovered the issue, I opened the fuse box and it smelt burnt. I haven’t driven the truck in an about 2 days so I don’t think it was from something else. That’s why I believe its probably a fuse. But clearly I’m not knowledgeable about this at all. Maybe I should just take it in to someone? Again, clearly wiring isn’t my thing. Because these complicated wiring diagrams and what not is no help.

 

Can you confirm your truck is indeed a 2002?

 

Interesting, no gauge lights work other than the battery light. 40A AM1
The battery light uses a different power source. 30A AM2
Bet you can’t guess what the wiper and washer uses?

The process for me wouldn’t be much different.