Hey all,

First of all, new here so thanks in advance for all the help!

Ok here is the story:

1989 Xtra cab 3.0 V6.

Yanked a fuse from the ECU to rescue another truck, and started the Toyota to move it and had spaced the fact that I had robbed a fuse, it was the ICU fuse. Truck ran for about 3 min and then I remembered that I had taken the fuse out and shut the truck off and replaced the fuse.

Upon getting things back to normal, drove the truck and noticed that we were on battery power based on the speed of wipers and such.

Did a quick test, no charge (at 11 volts), removed alternator, ran to NAPA, tested Alt and everything was fine. 14.7 @ 40 - 60 amps. Hmmmm, what the hell??

Placed tested unit back into truck, still no charge. The alternator is just not being excited to charge system.

Have charged battery and it holds a charge. Under a load the % of drop in voltage is acceptable. When truck is running I have 11.2 with accessories on and 11.3 with them off. (This is after a while of running.)

Checked wires in the back of the Alt, seem fine.

Checked the fuses, good connections, good fuses.

Morale of story: have no idea.

Has anyone esle had this issue? I have checked everything that I can think of. Have pulled the radio fuse to reset the ICU, (if that even applies...) Last I checked this is an internally regulated Alt?

Again, thanks for the advice, I am about to pull my hair out.

Have a great day!

~Brian

 

Well it's official, I am ready to pull my hair out.

So far after much homework, it appears that the battery light NEEDS to come on upon key turn or the charging system will not operate. With key turn, there is no light.

I have checked fuses, the bulb in the instrumentation, the printed circut board...

I am almost ready to admit defeat here and take it to the shop, which is frustrating, usually I can figure this stuff out.

I am wondering what two wires complete the circut to actuate the alternator to charge, there are 3 going into the pigtail into the alternator plug, hmmm, I wonder.

Any suggestions?

Thanks....

~Brian

 

Sorry I can't help you but I have been following this thread
https://www.yotatech.com/forums/f160...l#post50690981
and the 3 main guys in there, Elvota, fillsrunner4, and mt goat, all seem to have gotten VERY familiar with the electrical workings of both the 3.0 and 3.4 engines due to their swaps. Maybe they could provide some insight. Good luck.

 

You need to get hold of a Toyota Electrical Wiring Diagram for your year vehicle to be sure, but this is what I know from my '90 EWD... which should be fairly similiar.

Plug A, 3 pins.

R wire: from 10a "Engine" fuse.
Y-L wire: from 7.5a "Charge" fuse.
W wire: to 40a FL AM1

I believe the routing is: 7.5a "Ign" fuse, through the gauge "Charge Warning Light" and then on to 7.5a "Charge" fuse... then to alternator

Plug B, 1 connection

W wire: to 100a FL Alt.

Check all the related fuses and FL to see if any are bad.

 

That 7.5 fuse is in the fuse block under the hood, correct?

FL = Fuseable link, right?

Where are these in the path?

That is the one thing I don't recall checking...


~Brian

 

Thinking it over, I am going to assume that the FL is good, otherwise I would not have 12v @ the back of the Alt.

Upon talking a mechanic buddy of mine, I am starting to lean towards the charging system control relay. The issue is, where is the damn thing. I know that it is above the fuse panel, under the dash, but in the Sea of Relays, just where o' where could it be...

Anyone have a diagram to this thing that can give me a heads up on possible wire colors?

Or anything at this point, ideas?

Thanks!

~Brian

 

Actually, the related components are located in the fuse box, PS engine bay.

Here is a really bad pic:



7.5a "Charge" fuse is also located in this panel.
10a "Gauge" fuse is located in the DS kick panel inside the cab.

Hopefully with this pic and my original route description some of the pieces will start to make more sense.

Here is a link to the 93FSM which may offer some help as well:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

 

Elvota, if that is a bad pic, I am not sure that I want to see a good one, it looks pretty dang good to me. Thanks again for taking the time to help, I really appreciate it.

So far the survey says that it's the charge control circut relay. Where this damn thing is, is beyond me.

Finallly after beating my head against a wall and $10 in gas per day in a lifted suburban, the Yoder is in the trustworthy hands of JW Automotive here in Forest Grove. Two ex-dealer Toyota Certified Tech's that became tired of working for the man.

So, we shall see, more than likely later today I will have an idea. And hopefully, not hit the wallet toooo bad.

I shall keep you posted...

Have a great day.

~Brian

 

So did you ever figure it out what was the problem ( im having the exact same one...

 

help out a fellow portlander!!!

did your shop guys figure it out?

I have the same f(&^ing problem. battery was toast from too many overdrains, replaced it and 3 days later the alternator kicks the bucket. so I replaced the alternator (I suspect it had it coming, I had a leaky radiator hose that was dripping onto it for a year) and now the charge and brake lights are off when running, but the charge light doesn't light when ignition is on/not running. and it's not charging. it's a good thing I just changed my battery, because I had to drive home from mcminnville in the dark with no alternator. I made it home, but the needle on the battery meter was flat and it pegged out the meter on my charger when I plugged it in...

and I have no clue what to do next to fix it. everything seems like it's supposed to be...

 

Welcome to hell!

haha

Check the fuse on the kick panel by the clutch, make sure that it is not blown or just pissy in general. I believe it's the engine 10 amp. I would check them all, 90% of the time, this is the problem...

Let me know if you need further help and I will tell you what I know, but that is where I would start...

Good luck!

~Brian