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Alt went out. Now tach and rear anti-lock brake don't work.

After 305k miles the alternator died. Well, it still worked, but drained my battery overnight. As I was trying to figure out was zapping my battery, I pulled the 80amp alt fuse as the engine was running. Don't EVER DO THAT. The battery voltage fell, engine slowed down, and the wondow wipers turned on ultra fast speed. Far faster then normal and shook the truck from side to side. (Warning Warning Will Robinson!) I shut everything down as fast as I could.

Since it still worked, I connected everything back up and headed to the dealer. I noticed the rear anti-lock brake light on. About half way in, the alt started to overchange the battery. I turned on the lights and the fan and that seemed to keep the voltage down.

On the way home, the tach quit.

I install the new Toyota alternator without issue. It works fine. But the tach is still dead and the rear anti-lock brakes light is still on.

I tried to run the self-diag on the anti-lock, (I have the all the books on the truck), but the light just goes off. No blinking at all.

Where should I look next?

Oh, truck is a '93, 3L V6, SR5, manual trans.

Thanks

-Eddie

Reply to
Eddie
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Eddie schrieb:

Congrats. You have ruined the electronics by massive overvoltage due to load dump (no battery). Get friendly with some high-cost replacement parts.

Axel

Reply to
Axel Hammer

In fact, the bettery was connected at the time. It was the alt I disconnected. If it did do a load dump, it did it over the RPM, Battery light, and that other small wire that is plug into the back of the alt.

And I had my meter on the battery. The voltage went down. I think to 13.5 or something.

The ECU says it's fine and the truck runs fine.

Reply to
Eddie

Eddie schrieb:

Sorry then, but it makes no sense to me even if my first statement may be wrong. If the voltage drops your wipers should get slower. Is this a 24V vehicle? And what exactly connects the 80A fuse? I may be right, though! Check it out.

Axel

Reply to
Axel Hammer

Stumps me too. It's a normal 12V Truck. And they wipers turned on by themselves, and went really fast.

It's the 80A fuse located in the fuse box under the hood. It connects the Alt to the battery. It's marked Alt fuse. It's the pathway the alt uses to charge the battery.

I think you are right in that stuff fried, but I want to know why. So if they alt fuse blows, it frys everything else? What is going on?

Reply to
Eddie

When you removed the alt fuse from the system, the alternator was no longer connected to the battery and did go full load. You need to check the other fuses now. Any system that was on when yoyu did this will be effected by the large surge you put on the system. Not only in voltage, but amperage too. Whatever amperage you alternator is rated at went through these systems.

Reply to
mdouglas

But with the alternator fuse removed, would not that disconnect the alternator from the entire system?

Reply to
Eddie

No sir, that just removed it from the positive side of the battery. It was still connected to the electrical system of the truck.

Reply to
mdouglas

Wait a sec. So the fuse marked Alt, does not in fact disconnect the alternator, but disconnects the entire electrical system from the battery? And the alternator is still connected to the electrical system?

Then should that fuse be called master fuse or something?

Is this common on all Toyota's and autos in general?

Someone must have been hitting the Saki hard when they wired this thing.

Reply to
Eddie

Eddie schrieb:

AFAIK this is on all vehicles almost identical.

Axel

Reply to
Axel Hammer

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