Alternator harness 4.0 liter V6 pre-runner w/ tow package question

Can anyone here tell me if their alternator harness has 3 wires or is it supposed to have 4? Thank you for any help.

Joe

 

Sorry, forgot to mention it is the 130 amp Denso model

 

I've never even looked at my alternator, except when I replaced the serpentine belt.

According to the schematic, it looks like the 4.0 with the tow package has 3 small wires and the heavy output wire. Apparently the 2.7 has 4 small wires and the heavy output wire.

 

Thank you, I'm having the weirdest problem with my truck:

The battery light came on on Halloween. I replaced the alternator (factory one) with a new AutoZone one and belt and the light is still on. I checked the battery voltage at 12.6 volts and with the truck on it is between 14.1 - 14.4 volts depending on loads. I checked the wiring coming off the alternator, all the grounds, and made sure the battery terminals/ posts were clean. It's at the dealership now and even they are having difficulties finding out why it won't go out. If anyone here has any ideas I really appreciate it.

 

People here have had that problem and it turned out to be a corroded wire in the harness in the 3 or 4 wire connector at the alternator.

https://www.tacomaworld.com/threads/battery-light.144814/#post-18685899

Also, I wouldn't put a whole lot of faith in that AZ alternator.

 

Just got my truck back from Toyota and the technician says it's the AutoZone alternator I put in a week ago. It was supposedly a new alternator but he says the voltage regulator is grounding out internally causing the battery light to come on. The system is working as it should otherwise. I ordered a Toyota alternator and will have to fight AutoZone to return their defective one I have currently installed on the truck. They don't like to take back a used part but how would you know it's defective until you install it? Anyways, hopefully the factory one fixes this. Thanks for your help.

 

I just replaced mine a few weeks ago and almost everyone on here told me to stay away from the part store ones. I ordered a denso from rockauto which is oem

 

The only reman alt i would trust is Denso

 

The battery light issue continues!! I got a Toyota reman alternator last night (Denso) and put it in this morning - battery light still on - what the ??? I did check the wires coming off the alternator harness and didn't see anything obvious. It was at Toyota twice last week and they finally said it was the Autozone alternator I put in. The original Toyota alternator started doing this, replaced it with the Autozone one, and now the Toyota reman one. Any other ideas out there would be greatly appreciated.

 

This. If you've ruled out the battery the next step is chasing defective wires/ connectors

 

Is it possible rats have damaged the wiring?

Considering the post Mudinfun posted I'd take a serious look at the plug. If it has dielectric grease clean all of the grease out and look for discolored electrical contacts. Make sure you use dielectric grease when reinstalling whether the factory used it or not.

 

Time to start tracing wires, really sounds like a bad connection somewhere, corrosion or something of that nature.

 

Well fellows, I looked at the wiring again after having Toyota look at it for a couple days as well and I really didn't see it the first time but the white wire about 3" down like someone else was saying was the culprit. It wasn't very obvious that it was cut but it was and only hanging on by the outer sheathing of that particular wire. Thank you all for the help.

 

WOOOHOOOO! Now go tell your Toyota dealer you want your money back for the diagnostic time since they failed to correctly diagnose the problem.

 

Yep, been trying to get a hold of the service advisor and no return call yet so he must of figured he got caught lying.