River_Rat

Before I forget:

Its an ’87 4runner, 5 speed, 4x4, 4 cyl. 22RE (only had it a few weeks)

PART 1:

Hi Guys. I don’t know too much about electrical, but have been reading tons lately. Been loving the Toyota and YotaTech experience, until the other day anyways. So I’m driving home early Sunday morning after a 24 hour shift at my college placement, and head to the school by my house to do the first doughnuts of the year, got a good dumping of snow. Just before I start the first one I look to the dash and:

- My Tach isn’t working
- The voltmeter is dead
- The charge light is on
- The temperature gauge is dead (it only works sometimes anyways)
- The oil pressure gauge is dead (but its always been that way)

It’s still running fine but figure I better get home quick time. Check the fuses and the fuse isn’t blown but the fuse and panel are melted. What does this fuse usually control? Looks like hack job wiring under there, damn P.O. Notice all the loose connectors to nowhere.





When I get to looking at it. Starts up fine, I do the ‘ghetto’ pull the positive battery cable off test, and it dies, so I assume Alternator. I pull the alternator, clean it off and take it to the local electric shop, they test it and say it putting out lots of volts and amps, its pretty packed with dirt/grease though. I put it back in and same thing.

So I get the old multimeter out:
Alternator Plug reads like I think it should:



Does the change of only 0.2v sound right if its been running for 20 minutes? Maybe its getting some power? I’m assuming somewhere the problem is in the wiring harness now, doesn’t appear to be any hacked wires, they are pretty dirty though so I think I’d need to pull it apart to really tell.

HELP!!! What is my next step? Which wires go where? Which ones to check?




PART 2:

I’m thinking about replacing the whole wiring harness since it looks like such a hack job and I’m not too good with electrics, good idea? bad idea? Also my wiper motor is pretty old, the driver side power window barely works, and the rear glass is missing and I don’t think the motor works either. So I was thinking about buying another 4runner to part pieces from. Who ever helps me out here gets first dibs on the other parts.

What are my options for getting a new one or at least new pieces, new wiring harness?
Can I just rewire it myself, I’m not too electrically inclined though?
What years/models of 4runners/pickups are compatible, I think I found a decent ‘86?
Does it need to be manual or is automatic ok? 22R ok?
Will the seats, gauges, etc. bolt right in or do some things change in these years? I’d like to replace the rear seats.


Thank you very much in advance for all of your help guys. Do you need any more info?

Went Wheelin for the first time last weekend, buried her up the the body in a puddle, but got her out.

abecedarian

do you have 12v+ from the main white wire to the alternator?

TacoNut

The Voltage with the engine running should be quite a bit higher, like14-15 volts. That would indicate that the alternator is charging the battery. If the alternator tested good, maybe you have an external regulator and its bad.

River_Rat

Thanks so far guys. Yup 12.5v coming from the white wire. And I am aware that it should be charging higher than 12v. Does an 1987 usually have an external regulator? I thought the regulator was built in to the alternator? Could I still have a faulty alternator even if it tested good?

On my compatibility i found a wiring harness from a 1987 4cyl 5spd pickup. I'm assuming that it would be compatible. what do you think?

Anyone know what my burnt fuse controls? it is still getting power when I stick the voltmeter in either side. what does this mean?

Thanks again.

abecedarian

so you got 12v on both white wires, 11.7 on the red, and almost 0 on the yellow? hmm
have you checked the 'charge' fuse?
is the ground wire from the alt harness good?

River_Rat

Thanks abecedarian and sorry for wasting your time.

Wow do I feel like an Idiot.

It definately was the 'charge fuse'. That'll teach me to check fuses at night. But I guess it will soon be time for a new alternator if its only charging at 12.5volts. That was a lot of extra work pulling the alternator for a 5 second fix, gues thats my punishment for being stupid.

To turn this into a positive, I'll do a little write-up of my idiot move.

But sill does anyone know what my burn't fuse controls, could it be the power windows cause they're not working lately, maybe I should go check the fuses first. lol.


Thanks again everyone.

River_Rat

After my Idiot move, in YotaTech style I'd thought I'd do my first little write up to help others from making the same dumb move.

Indicators your CHARGE FUSE is blown in a 1987 4runner:

- CHARGE LIGHT is on
- Tach isn't working
- Voltmeter isn't working
- Temperature gauge is dead
- Signals don't work

abecedarian

so, it was the 'charge' fuse...? wonder why they called it that? ...
now having laughed a bit....

I will admit, I feel small for not asking about the fuse first. When you said you had 12v at the alternator output wire (the large white wire) after my inquiry, the next thing I did was go back to the pic you posted about the voltages you measured at the alt plug, and look at a wiring diagram for an 87. Then I realised that the 'dummy wire' as you called it, is the return path from the charge light (and choke heater for those with carburetors) through the regulator so you should have had 12v there too. Yes, I am going to slap myself... probably more than you can imagine.

For the record, I'm here because I have time to spare so don't think you wasted any of it.

But now I'm going to ask, after running a bit, you've still only got 12 volts or so at the battery? That is not right. Should've gone up to at least 13.5 or maybe more. So check the voltage at the LARGE white wire, where it connects to the alternator.
You said the parts shop said everything was okay with the alternator (volt and amperage output tests okay), but if so, given the wiring is straightened out (in particular that charge fuse), the ouput terminal on the alt should have close to 14.5-15.0 volts on it. If you are not getting more than 12.5 or so volts at the battery there is something else going on.

River_Rat

I definately feel like an idiot. I think I may have too much spare time lately too. Anyone know of a good online dating forum. lol. Ran outside after reading your post. The Battery is now charging nicely at 14.4v, wonder why the fuse affected it so much.

Thanksagain for all the help, I owe you one.


Still anyone know what my burnt fuse controls, it was a 20A.

abecedarian

the fuse effects things so much, because it is part of a 'feedback' loop to the regulator. the ignition key supplies voltage to the regulator, but only as a 'reference' signal and has little bearing on the output. the regulator needs another voltage source to say it needs to charge (raise output) and that comes through the charge fuse.

as for your burnt fuse, it appears to be the 15A fuse for the EFI.

guess there's no kanji for "EFI"

TacoNut

Sorry, I wasn't sure if you 87 had an external regulator. I just knew you had tested the alternator, and charging voltage should have been much higher. I guess I shuold have known I used to have a 90 2wd pickup and it had an internal regulator. I didn't know about the fuse, but makes sense, kept the regulator from doing it's job. Glad you got it fixed!