Help!!! Trying to help my friends Altenator problem

I’m new to the form so I apologize if I do something wrong. I’m 70 and this is all new to me. My friend is 75 and was passenger in a head on car wreck leaving his right shoulder and arm barely able to use so here I am try to help. Please help me if you can to get his truck running. Thank you

This is a 2006 mfg date 4/2006 2.7 4cyl Tacoma 2door cab. Here is what he has told me. Drove about 20 miles from home stopped turned off, battery was dead would not start. Put new battery in drove for several days short trips again drove 15 to 20 miles killed it won’t start battery dead. Took to local mechanic, he replaced alternator and pigtail saying both bad. It same thing week later short trip ok longer battery dead. I got meter out, it’s not charging at all, also noticed battery light in cluster will not come on. I’ve checked fuses all are good, I’ve repaired all wires I can find that are bare or broken. I’ve taken all ground straps wire brushed under all I can find. At this point I don’t know that mechanic may have wired pigtail wrong reading what I have it’s really easy to do. Here are the voltage on plug w/key on and off




Top right plug white, to pink on harness



Going to white on harness

bottom left blue on harness

Bottom right to gray on harness

 

I believe there is a 140A fuse (F36) under the hood. I'm new to Toyota so that's all I got.

Edited to add that there is also a 7. 5A (Fuse 8) fuse also under the hood for the charging system.

This info is for a 2012 Taco. Don't know about 2006.
The local mechanic shouldn't have let this go not working.

 

Careful shoving the meter leads into the connector, if they are too big they can permanently spread the terminals and cause them to not make a connection.

I see the connector has been replaced, are you sure it is wired correctly?

The White wire (Pin 1) (Voltage Sense) should have battery voltage, it comes from the ALT-S fuse 7.5A in the underhood fuse box.
The Pink wire (Pin 2) (Ignition Power) should also have battery voltage, it comes from the IG1 fuse 10A in the interior fuse box.
The Grey wire (Pin 4) (Warning Light) should read near battery voltage, if you ground it the charge warning light should turn on.
The Blue wire (Pin 3) (Monitor) I believe is only used on the 4.0L engine.
The heavy White wire to the eylet should also have battery voltage, it comes from the ALT Fuse 120A in the underhood fuse box.

If the fuses are good and the connector is wired correctly but the voltages are missing you will need to track down the broken wire(s).

Wiring diagram for the charging system.


Connector view looking into the connector side.

 

Could be bad alternator...sometimes they are bad out of the box

 

Thank you I use your info and pigtail is wired correct. I recheck fuses today and the 7.5 ALT-S was blown. Replaced thought I had it but still don’t charge. I had the ALT checked at AUTO ZONE 4 times but those guys are not tech’s. Question I see in the info showing the battery light, I’ve checked several time the light does not come on? Do I need to get another ALT? Please let me know anything else I can check. Thanks

 

Did you verify the light circuit by grounding the grey wire with the key on and checking that the light illuminates and double check voltages on the other pins?

 

Does the pink wire have batter voltage to it with the key ON?
In your first picture it shows .08v? That’s not right. It should be what ever voltage your battery reads (12.6~)

The pink wire turns on/off the regulator. If the regulator is off your alternator won’t charge.

Unless I’m completely wrong on how this works? @Dm93

 

Correct, both the IG and S terminals have to have power for tje alternator to work.
Some have to also see voltage on the L terminal from the warning light as well although I'm not sure if the Tacoma does or not.

 

2006 Tacoma 4cyl 2.7. Yes when I ground out the pink wire the battery light does come on with key on. This is the only time I have seen it since I started working on it. I checked voltage on pink and it reads same as in my original photo All other terminals are read same as battery. Where do I go from here. You guys have no idea how much we appreciate you. Thanks

 

Check the 10A IG1 fuse. Make sure it has power to both sides of the fuse with key on. If it does, we’ll then need to move on to the connector between the IG1 fuse and alternator.

 

Something is screwy if the light is coming on when you ground the Pink wire, that should be Ignition power and the Grey wire should be for the light.

Are there any other wiring repairs that were made where wires might be crossed?

 

Wow, I missed that part. Grounding the pink should have blown the fuse.

Something isn’t right wiring wise.

 

Would trace the wire at the connector back to the IG1 fuse help. I’d like to know what wire goes to the IG1 fuse.

Something is wrong.

I’d do a continuity check from the fuse to the connector. Key off of course. Or better yet, remove the fuse to be safe.

 

N E W - Never Ever Worked

 

Been long day today but really good good day. Sorry guys it was gray not pink made light come on. As you suggested I went back to IG1 it was blown, I’m embarrassed I can’t believe I missed that. . I been working on this truck off and on since MID July. You guys have made my friend super happy he’s got wheels again. I do really appreciate all you guys. Thank you again.

 

Thanks for the update.

At least it was something simple

 

Been tricked too. Pull a fuse, looked good, put it back in, look at a bunch of other stuff, go back to the fuse, test it this time, looks good but fails testing.