Charge and brake light cam on. So like all my other previous toys, i checked the brake fluid level first and finding it full went and replaced the alternator. Always turned out to be the alt.

After installing the new alt, charge and brake light still on. Never having dealt with this and having very limited electrical knowledge, i searched and everyone said get a multimeter and check everything.

After charging my battery to full, i checked it...12.6.
Started truck. Checked at battery terminals....12

So no Chargy. I decided to test at the alternator at what i assume is the power to battery (the wire held on by the nut, not the plug)
Testing that found it to be same as the battery.....12.

My question...
When testing the alternator at that spot, shouldn't it be reading around 14 or 15 volts?

 

When you tested at The B terminal on the alternator if the engine was running you should get around 14.5 VDC if all was working as it should be.

Engine not running the battery voltage is what you will get.

 

Sorry I wasnt more specific.

Battery charged. Truck off. Battery reads......12.6
Engine started. Battery reads...12
With engine started testing at alternator reads 12.
Figured it was just getting same as battery.

So looks like the new alternator from Napa not such a good deal. And they've been so good to me in the past.

Thanks for the quick reply.

 

It happens now and then.

They are most often pretty decent about things like that

 

Like Wyoming said ^^

Changed you mind?

It is never a good deal throwing parts, money and time at a problem when you have not verified that the part you are replacing is bad.

See alternator link on my sig for test points for charging system.

 

Thanks Rad4, I'll be checking out the alternator link after this update as the mystery continues.

Yeah, i know it's not a good idea to fire off the parts cannon but like i said before, it was always the alternator in the past so i did what i usually did. And not knowing much about electical stuff i just went of what my dummy light was telling me...like a dummy do. How's the saying go..."Good judgement comes from experience...experience comes from bad judgements." I'll be testing a lot more on the truck since i found this wonderful wealth of knowledge that is Yotatech.

So this was my Sunday...

Took the alternator back, napa tested it. It was bad like i told 'em. They got me another, had that one tested and it's good. Yay.....

Installed it. Started truck. Charge light still on!!! So by now I'm getting pretty frustrated. Checked all the connections and I had already checked and rechecked all my grounds but i checked again. Checked the charge fuse too. All good.

Tested again...Truck off. Battery...12.2
Truck on. Battery....11.9
Truck on at B terminal on alt...11.9
same as battery again

By this time it was getting dark and cold out so i put the trickle charger on and decided i'd do more research and come back to it when i could.


Monday..started truck. charge light on. Gauge looked to read at about 11 or so. Work. Drove home with charge light on again. Didn't have time to research. Battery on trickle charge for another couple of hours til charge.

Tuesday...Started truck. Dash gauge shoots up to about 16 or so and charge system appears to be working. Worked on the way home, too. Some people may have been happy but to me it just meant that there's a short or some other issue under the hood that I'm gonna have to chase down.

 

Possibly a short or just that your alt is still not putting out anything; that's why with normal load your battery voltage goes low.

If alt is OK. check IG (thin red wire on to connector). You should have 12V there. If you're comfortable removing the pin from connector housing, do so. Reconnect connector and do check on wire side (that goes through some switches/fuses back to batt).

re: Charge fuse - That does not actually cause alt to charge. It is a fuse for the error light circuit. If you remove charge fuse, your charge light will go out, but does not mean your problem is gone -LOL!

 

will do and post results. thanks again.

 

When you say remove pin from connector, do you mean the connector housing that latches on to the alternator? The three prong connector?

 

I'm assuming that you have verified that your battery is good, and that you are referring to the schematic.

Correct.

Better yet, before you do this, however, please check if your reverse light works. That could indicate that engine fuse is blown.
Circuit is retarded (Back in those days, Toyota had better mechanical engineers than electrical engineers) - ENGINE fuse supplies reverse LIGHT, alternator, power window relay, neutral safety switch, light reminder relay, and ECT. Yes, those are engine parts- DUH!

disconnect that connector from alt, and measure IG pin (See schematic on my post). You should have steady 12V there when IGN is on - even if engine is not started, yet. IF you do not get 12V there, trace circuit back to your "Engine" fuse.

Once you have verified IG voltage, it's still a good idea if that voltage remains steady when engine's running (alt supposed to be generating).

You can simply:
Poke the insulation or thin (red?) wire with safety pin, make sure you contact wires inside. That could be your test point "IG"
Reconnect connector,
Measure voltage there. There should be 12V steady when engine is running.
With 12V at IG, battery good (no internal shorts- if that condition even is possible), there should be approx 13.5 - 14.5 V at "B" post/terminal of alt. If none, alt (windings, brushes, slip ring or regulator) is bad.

 

Out of habit I always install rebuilt alternators with the battery fully charged.

Do these alternators have the issue of taking out the diodes when installed on discharged batteries ??

When you mean checked your grounds did you remove them and clean all the lugs and bolts and battery terminals??

I have seen extreme temperature changes make the difference between a good connection and a poor one.

Another thing sometimes I do these things out of habit and don`t even think any more but the pins in the alternator plug do get corroded !!

You might not be able to see it but it is enough with the plug being where it is to cause the problem of a no charge condition.

 

Got to digging around and found this....pulled out the clips and prongs, cleaned em' all up. Reconnected.

Tested the ig wire at the alternator side of the purple and black plug pictured. Read 12.5
From there the ig wire went to a green oval sized plug, then to the regulator. Back to the green plug and then to the alternator. So I tested the ig wire in between the last green plug and the alternator. Read 5.54.
Started up the truck. Charge light on. Bastard.
With truck still running, got back under the hood, crammed and pushed all the wires as far as I could up into the regulator box. RPGs then dropped a little. Checked the dash...charge light off. Cute. Really cute.

Soooo, as far as I can tell, the only way into that regulator box is with a can opener seeing as though it's pop riveted together. Guess I'll just try to immobilize the wires until I can find me a new/working replacement.

Thank you both, Wyoming and Rad, for your imput. Turned out the issue was Mickey Mouse, but I now know what and how to test.

 

So you mean wiring's not same as schematic?

IG entering Alt/regulator at connector is 5.54B and not 12V?

 

Well, I don't really know. The schematic is a little confusing to me. But here's what's going on on my rig.

With truck ignition in on position......Plug on bottom right is purple and black. It's got electric tape on it cause the clip is broken. Red ig. wire going in and out tests 12.5. From there it goes into the green oval plug. There is 5 wires that go from the green plug to the regulator. The white one with the red stripe test 12.5 so I assume it's the ig. The white wire with the green stripe from the regulator to the green plug tested 5.55. From there it goes onto the green plug ant the wire connected to that prong is yellow. It goes from the green plug to the ig prong on the alternator.

Since it the ig wire had 12.5 going in and only 5.55 coming out, I assumed something inside the regulator wasn't fully connected. Couldn't really tell cause I'd have to break it to get inside. So I started the truck...got ahold of the five wires that run into the regulator and I pushed them as far up into the regulator as I could. The rpms dropped a little and when I checked the dash the charge light was off and the gauge appeared to read about 16 volts. So something isn't fully connected in the regulator. No other explanation as far as I can tell.

 

I did notice however the schematic says 22re. Mines carbed. Don't know if they're the same. It appears the P.O may have messed with some of the wiring but it appears to all go to the right spot even if the wire colors are different.

 

Yeah, you seem to have different components. Don't know if they're stock. Only a proper schematic of fellow owners of same model can tell. But regardless of physical components, alt circuit should be pretty standard:
IG to provide excitation current to generate voltage,
S = sense to sense battery voltage, when Vbatt low,add more current to windings to increase output voltage
B = alt output to battery.

 

Out with the old....in with the new. It's not a toyota factory part but it'll do. Voltage regulator from napa-$45 Now I got my crappy heater back, the headlights ain't as dim and it actually runs better too. Don't really know what that's all about.

Thanks again for the help you guys.

 

Glad you got it fixed, Man!