95 3vze rebuilt alternator, not charging again
 

I had the local guy in town rebuild my alternator (who only business is to rebuild alternators and starters). He is a professional, gave me back my old bearings, brush housing, diode pack, etc... He bench test - OK say "here you go". I install right back into the truck again. Turn the truck on, starts - runs. Red battery light in the dashboard still light. I disconnect positive lead on the battery - POOF, engine shut off immediately. I have my battery on a 2-amp trickle charge the whole time, it reads 12v - 13v

I spent some time reading the FSM, and am confused with the information - does not appear to explain very well the plastic 3-wire connector to the alternator, which one of the leads I need to toggle to test bypass of the truck wiring for me to activate the alternator when truck is on just to test make sure nothing happened between the test on the bench and install to the truck.

FSM explains there are 3 fuses "Engine 10a, Charge 7.5a, IGN 7.5a". I see there is a "ALT 80a" on the EXTERNAL fuse box, which the manual fails to explain and I can not seem to find the "CHARGE 7.5a" fuse, where that would be or how I would check that.

In any event, the alternator is not charging and I was hoping someone can help me with advice. I would like to troubleshoot from here where to go, what I can do with the 3-wire plastic plug how I go about with my test leads check voltage or ground in-between any of this, please.

https://cimg7.ibsrv.net/gimg/www.yot...94a5e0ecd7.jpg
Exterior fuse box
https://cimg9.ibsrv.net/gimg/www.yot...c97fd10dac.jpg
Interior fuse box

I spent 15 minutes trying to find the awesome writeup about this that was on page one yesterday... Just can't find it.

7.5 fuse in above the driver side kick panel (floor)

Ground are all good?
https://www.yotatech.com/forums/f116...-guide-194413/

I am not sure if the grounds are all good. I have 3vze engine, the link you provided shows me a 22re engine. I can test GROUND to the case of the alternator, from the battery.

Missed the engine reference in the title.
https://www.yotatech.com/forums/f116...4-3-0-a-84413/

While we're here, does anyone know how to replace the 80-amp fuse in the external fusebox for the alternator? I managed to blow that out in my frustration with these wires and the 10 things in the way. I manage to pull off plastic housing and there appears to be the terminal leads STUCK into the fusebox housing. I can take a pair of needle-nose pliers to them, and they are not coming out without a severe fight.

Take out the box, flip it, remove the screw holding in the 80a fuseable link. The other 2 "big ones" are screwed in as well.
If you snap off the cover, don't worry about it. I have been driving for 15 years without any covers on the fuses, because I learned AFTER snapping them off. :)

I am guessing the designer for this wonderful feature did this as a gesture of gratitude on their last 2-week notice working at Toyota.

My advice? DON'T do that again. Back in the day of mechanical everything, you could sometimes power the ignition from just the generator and get away with disconnecting the battery like that. For the last 40 years, though, vehicles are full of solid-state components (diodes, MOSFETS, etc.) that will easily die with a spike like that.

That includes the range from "normal" (13.7v), "not charging" (12.6v), all the way down to "completely dead battery." (12.1v) Use your multimeter, you need a more precise measurement.

The '93 FSM shows a "charge" fuse in R/B 2 http://web.archive.org/web/201204170.../2powersou.pdf where you have no connection at all. My '94 EWD shows no charge fuse. I don't think my '94 has one, but I'm sitting at the computer now and would need to go out and look.

Have you back-probed the three wires to the "plastic" alternator connector? With key-on, engine off, you should get battery on Red (#2) and White (#3), with ground on yellow (#1). Running, you should have about 13.7-14.1 on all three.
You would NOT be happy if the 80amp fuse tried to squeak by with just push-in terminals.

With engine off, key on - I read +12v on all 3 wires (Red, White Yellow). I have to splice test leads into this to test when running, since it will not run without the airbox connected. It is probably not safe to risk suck unfiltered sand & filth (also probably a missing 10mm socket) straight into the engine. The wonderful air intake hose is strategically placed to block me from tending to alternator while running.

If you have 12V at the red charge wire on the alternator then your alternator is no good.

My EWD shows the red wire connected to the ENGINE fuse, then to IGN1 in the key switch. So it SHOULD have battery with key-on.

Are you thinking of the Yellow wire to the ALT light? Remember that Stein measured the voltage with the connector unplugged, so the alternator couldn't ground that end, and he would just be measuring battery through the ALT light.

I connect multi-meter set for current, through the big alternator terminal that goes to the fusable link. The plastic 3-wire connector was plugged in. I turn the truck on run. Again with the RED battery icon on the dashboard.

The multi-meter is reading DRAIN 0.002 amps, on that line. The alternator is definately NOT sending any current out. I discover, when I disconnect alternator charge terminal wire - the RED battery icon shuts off in the dashboard. At this point nothing would be charging since the alternator is only connected by the 3-wires in the plastic plug. I re-connect the charge terminal wire (wile it running) and the red battery icon lights up again.

You might need to check the internal fuse in your multimeter. My good multimeter has a 10amp maxium; your alternator (if working) can exceed 10amps. Unless you are very unlucky, that would blow the ammeter fuse. In which case you'd always see very tiny (e.g., 2ma) readings.

Assuming your ammeter is reading correctly, then your alternator is probably bad. Here's the FSM for testing the alternator; all that really adds is how to check the regulator. http://web.archive.org/web/201102051.../2onvehicl.pdf Or, you can pull the alternator and take it to most auto parts stores for a free test.

If you want to one more test, I'd look for the voltage on the red wire and "fat" wire with engine running, and voltage at the battery posts with engine running. You'll probably find just battery voltage (~12.6v) on the battery posts, which tells you what you already know: not charging. You should have battery voltage on the red wire (you checked that with the connector disconnected, but checking it under load is useful). Last, if the terminal for the "fat" wire reads more than battery voltage (e.g., 13.7-14.5), the alternator may be working but the fat wire isn't making it to the battery.

You can use insulation-piercing probes to measure the voltage in insulated wires. https://www.ebay.com/itm/2Pcs-Safety...-/113283657316

I don't think your 10mm socket will make it past the intake valve, but fortunately the engine won't run with the intake disconnected. You have a fuel-injected engine, and it needs the signal from the VAF.

Yea I realize that now after I am relaxed and done making no progress for hours. I realize I have a clamp-on meter for high current tests, which would have made it a whole lot more easier for me. The fuse in the one I was using actually FELL OUT and was rolling around in there. Somebody should start making these meters with the battery door bigger so I can just swap the fuse or the battery with a hinge instead of me dismantling 8 screws to disappear.

I have the alternator out. Now I have to ring something up with wood, a rubber wheel a hand drill or something so I can spin this and give it power without 20 things in my way and dangerous spinning fan.

Ok today the alternator is out and on my bench. I hook up a drill with a socket, and drive the alternator at the fastest speed the powerdrill goes. I have GROUND hooked up to the case of the alternator, which I have tested good continuity. I have +12v attached to t he CENTER terminal in the plastic plug. I activate the drill. The output charge terminal registers 300mv at the highest. There is NO sign of the alternator engaging and giving ANY resistance to the spin of the drill. The alternator will not charge, and fails the test.

Can anyone find anything wrong with this test?