Battery indicator lit... No CHARGING after new motor installed

I have a problem I haven't been able to resolve.

05 Taco with fresh motor dropped in. Runs like a champ... so quiet and responsive... but BAT light is on, alternator is not putting out to batteries.

When I was first re-connecting all the electrical, I did BLOW #39 fuse OPEN Shorting the ALT ground wire to POS BAT terminal. I replaced it with an AutoZone branded fuse with same rating (120)

1. New AGM Batteries
2. Alternator removed and tests good.
3. Ground wire from Alt to battery NEG terminal has continuity
4. Each of the wires in ALT wire harness to Fuse box has continuity.
5. All fuses verified good including #39

Been at it a couple days... getting good and frustrated. Any ideas?

 

This might help:

 

What about positive terminal of alt to positive terminal of battery? Continuity?

Electrically that should be the same place

 

What's ur battery voltage when the truck is off ? Then what's the battery voltage when truck is running?

 

Thank You

THIS was the post that really got me thinking and shook the cob webs loose. Then, going to the reply above... kinda confirmed!

It's been a very long (MONTHs) evolution getting this engine in. In the process, saw my Tranny mount broken, and literally nothing left of my CB! There has been so much work done... and here in AZ... it's been hot. I mention all this to try and get sympathy for my lack of attention to the BASIC F'ING wiring!!!!

Notice, in my original post I didn't mention the positive cable from the ALT to Battery!!!! I'll get it all reassembled tonight / tomorrow adding a positive line from Alt to Batt. I don't think it should even need the NEG as the motor is grounded, and the Alt is bolted to Motor.... Yes?

Same of course.

My next question will be something in the lines of "Can I fit 35's without a lift?" LOL

Thank you all, I think I'll be all set by the end of the day tomorrow!

 

for grounds..

There will always be a battery to frame cable, battery to engine cable, usually near the starter, and a engine to frame cable (sometimes 2)

Make sure they're both snug

 

Yup.... During my lunch, I pulled both batteries and all Off Grid equipment/wiring. I then put the alternator back in, reconnected the fuse box plugs/wires. Made sure ground is solid from Engine Block to frame, and battery to frame (though disconnected at this moment).

Once my work day is over, I'll get back to it, keeping it simple. I will leave all my accessories (LOTS) disconnected and just start with one battery, hook up starter and alternator, and see where I'm at.

Fingers crossed, and hopefully not wires!!!!

 

It's rare but recheck your wiring for corrosion or damage due to the short you experienced. Continuity tests are great but if only one wire in the strand is connected or touching it can show continuity. Sometimes the crimp, connector, or wire looks good but the problem is just inside the jacket.

It's probably not the problem, but if you are stumped, it's worth a check.

 

And finally, time for accessories! Thanks for the input!

 

What did you do to fix it?

 

I hate being a moron... and making dumb mistakes.... but as I said above, I didn't have a positive line from ALT to BATT. Most of my wiring has been replaced over the years (Original owner) and the ALT + Cable is Black with Black ends. I didn't think it through. It had been a very long evolution replacing the motor.

 

The OEM wire goes from the alternator to the fuse box, through the fuse and then to the battery. You didn't hook up a wire straight from the alternator to the battery, did you?

 

I did. Inside the Fusebox next to 100 and 120A fuses is a bolt and wire. That wire leads to Positive Batt terminal also.
Are you saying that the ALT + should route through the side of the fuse box to that bolt?

 

The alt attaches to one side of the fuse and battery to the other side

 

So this AM I disassembled the fuse box (again). One side of fuse went to BATT+, the bolt I spoke of is an extention of the other side of the fuse and it went to positive. Then, the alt + also went to BATT+. Basically the alt+ wire I ran was bypassing the 120 fuse. So, I took the 2nd wire mentioned (in fuse box) and re-routed it to the alt +, discarding the now "spare" alt + to bat +.

I'm glad you chimed in b_r_o