Electrical Problems From an Amateur / Guy Out of the Wrenching Game (2 Viewers)

[michaelharrisco]

Regarding 1978 FJ40 (generally stock)

Folks - this is the first post I've made in a really long time. While I still have the 40 and the 100 series, the reality is after getting older and having 2 kids I literally have not had to do any work (or have the time to tinker with it anymore) on the 40 in many years. It just keeps cracking with very little trouble...until now.

My hope is maybe something is really obvious to someone else that will help me, but if I can't figure this out I may have to take it to an electrical shop in town (there is a really good one about 15 min drive from my house).

Here is the order of events to where I am today:
1) Noticed the turn signals were intermittent (have been solid flashing for years)
2) Headlights quit working completly
3) Would still crank no issues
4) 3 days ago, would not crack at all (parking lights / dash lights still came on)
4) tapped the starter with a hammer and it cranked up
5) now won't restart
6) was thinking it was a starter (it still might be)
7) tonight...around 3 days later no lights / she is dead completely
8) I have a rebuilt starter, but was not aware how different the configuration is (wire harness, size for mounting, etc)...aka this does not appear to be an easy R&R. I'm not familiar with the high torque replacements which this probably is.

I tried jumping, but doesn't seem to be doing anything (lights not coming on at all).

All fuses visually look good (I may replace all of them with new just to rule that out).

Seems like trouble for my rusty 40 maintenance skills since its been a while and I'm way better with mechanical repairs than electrical.

With all that said...any advice?

 

[kerplunk]

Wait, was that just taped together? That yellow in the earlier picture looked like a but splice to me...

 

[michaelharrisco]

Yep…just spliced and no fuse. Again been like this for over a decade and I was unaware.

Don’t joke this temp set up but I reput it back together with a cheap inline fuse and measured 12 V at the white main cable. See pic where my finger is where I measured 12 V going to white main cable.

Still not getting any power.

This is getting me concerned. It seems like it would be more difficult to trace from main cable going through firewall down to fuse box.

Am I thinking about this correctly as the next thing to check?

I’ll order a better fuse as posted for sale earlier but don’t feel like that is my actual problem due to this temp set up and still not getting power anywhere.

I also opened up steering column and looks clean . Pictured also included here.

Any thoughts?

 

[kerplunk]

From Toyota's service manual for a '75:

Battery -> fusible link -> White wire (that your finger's on) -> Amp meter.

Amp meter -> WL (White / Light blue line) to the Alternator and the ignition switch.

I don't see anything White / Light blue on your ignition switch, changes are if you followed the wiring up under the dash to the plug you would see that from the harness. But that should be mostly unnecessary, one of those four needs to be 12V, and it looks like there are markings on the back cast into the plastic, it should be "AM".

You should also have 12v at the alternator, again White / Light blue stripe, wire connected on the stud / nut "Batt" terminal.

If you don't have power at both points, pull the gauges and check at the ammeter (pull that fuse you just installed first).

And if you don't measure any power on multimeter, test lamp, whatever, make sure you do have it connected to a good ground, unpainted, etc. I try and work with something long enough I can reach back to the positive on the battery to make sure my tester is solidly grounded and not giving me false negatives.

 

[45Dougal]

Have we actually established whether there's power to the fuse box yet?

 

[ToyotaMatt]

what did this tell you ?

.

 

[michaelharrisco]

Have we actually established whether there's power to the fuse box yet?

no power across any fuses.

I’ll look through the wires under there to see if obvious where main power is coming into fuse box. I’ve never had to look back to main power coming into fuse box before.

 

[michaelharrisco]

what did this tell you ?

.





View attachment 3469072

Nothing…I was just visually looking.

Where do I even measure V here and is finding 12 V here a sign that 12 V are running into the fire wall main harness?

 

[45Dougal]

no power across any fuses.

I’ll look through the wires under there to see if obvious where main power is coming into fuse box. I’ve never had to look back to main power coming into fuse box before.

Black wire to chassis. Red wire to all fuses. No power.
Next stop...
Is there 12v at both sides of the ammeter?

 

[michaelharrisco]

From Toyota's service manual for a '75:
View attachment 3469024

Battery -> fusible link -> White wire (that your finger's on) -> Amp meter.

Amp meter -> WL (White / Light blue line) to the Alternator and the ignition switch.

I don't see anything White / Light blue on your ignition switch, changes are if you followed the wiring up under the dash to the plug you would see that from the harness. But that should be mostly unnecessary, one of those four needs to be 12V, and it looks like there are markings on the back cast into the plastic, it should be "AM".

You should also have 12v at the alternator, again White / Light blue stripe, wire connected on the stud / nut "Batt" terminal.

If you don't have power at both points, pull the gauges and check at the ammeter (pull that fuse you just installed first).

And if you don't measure any power on multimeter, test lamp, whatever, make sure you do have it connected to a good ground, unpainted, etc. I try and work with something long enough I can reach back to the positive on the battery to make sure my tester is solidly grounded and not giving me false negatives.

Def have 12 V on white wire on alt nut as described.

 

[michaelharrisco]

It got late / dark so I bailed on measuring the amp meter. For years the amp meter would sometimes flutter back and forth but then sometimes seem to work.

This is what I see now while in dash but I noticed when I removed + batt terminal it stays exactly the same.

It’s prob been 10 years since I’ve removed the instrument cluster. I was getting tired and felt like I was gonna break something so I stopped, but after removing the 2 main exposed screws the cluster didn’t want to budge / come out so I didn’t get a chance to measure the actual connections of the amp meter.

With batt and alt measuring 12 V and me verifying I see V going into that main white wire into the firewall it has me thinking it’s something in steering column or at the fuse box, but I’m really not an expert with this.

I’m gonna be with my father in law tomorrow who is a pro and I’ll ask him.

Any other thoughts?

 

[kerplunk]

Def have 12 V on white wire on alt nut as described.

Did you check the ignition switch? AM? (I would check them all, not trusting the labeling.)

That big gloop of solder on the back of it should be conductive enough to test on? If there's no power to any of those, follow the wire up to the plug under the dash and test for power there.

If there is power on the back of that switch, put the key in and see what gets power when you turn it

From the Haynes manual for a '74:

The Toyota manual for a '75 I "quoted" earlier claimed the wire to "AM" was WL and comes off the ammeter. Haynes claims the wire to "AM" on a '74 is BR (Black Red) and from the starter (on the same lug as the large gauge battery cable). I'd generally have more confidence in Toyota's manual, but I see the back of your ignition switch is Black/Red.

Both show power to the Wiper fuse from ACC on the ignition switch and power to IG / coil, turn and heater from IG on the ignition switch. Headlights, lighter, horn, tail lights, probably off the ammeter or something, my eyes are hardly good enough to follow this image...

Many of the diagrams are on @Coolerman 's website Cruiser Wiring - http://www.globalsoftware-inc.com/coolerman/fj40/wiringmainframe.htm

And some others are in the Chassis Body repair manuals at Land Cruiser manuals, FSMs, and repair resources - https://heritagecruisers.com/pages/manuals

 

[45Dougal]

It got late / dark so I bailed on measuring the amp meter. For years the amp meter would sometimes flutter back and forth but then sometimes seem to work.

This is what I see now while in dash but I noticed when I removed + batt terminal it stays exactly the same.

It’s prob been 10 years since I’ve removed the instrument cluster. I was getting tired and felt like I was gonna break something so I stopped, but after removing the 2 main exposed screws the cluster didn’t want to budge / come out so I didn’t get a chance to measure the actual connections of the amp meter.

With batt and alt measuring 12 V and me verifying I see V going into that main white wire into the firewall it has me thinking it’s something in steering column or at the fuse box, but I’m really not an expert with this.

I’m gonna be with my father in law tomorrow who is a pro and I’ll ask him.

Any other thoughts?

View attachment 3469154

The white wire carries current to the ammeter, through the ammeter, and onwards to the ignition switch and fuse box.
Since you don't have power at the fuse box, the ammeter connection is a likely place to have a loose connection.

Try not to short circuit the ammeter studs on the metal surround as you extract the instrument cluster!!!
Ideally you'd remove the battery cable but that doesn't help with the test.
Otherwise reach up blindly underneath and use the force.

 

[michaelharrisco]

First off…thanks for all the help. I bet some of this is so basic for y’all?

Good news/bad news?


Good news: I got it running and was able to move it into the garage. This will make it so much better to work on at night!

Def a burned / corroded wire to amp meter on dash as y’all thought was the next thing to check. See picture if curious.

Once I got that wire reassembled got parking lights back, but it was still dead on crank with key and still no headlights.

Used bypass trigger start device and it cranked and idled normally. First priority was to park it in the garage!

Bad news:
I noticed the heater fuse burned out and still no headlights. Still can’t crank with key?

I still plan on ordering online fuse as posted earlier to get that done right but still don’t think that is root issue.

With this summary of items I feel like I have a short somewhere. Any advice?


Worse case: I can atleast drive it in the day to a great electrical shop in town, but part of me wants to keep working this to completion. I’ll be reading any comments, but schedule wise I might not be able to work on it much the next 7 days, but man I’m glad it’s sleeping in the garage again!

Thanks again!!!

 

[kerplunk]

Wires just burning themselves is typically going to be from a short.

Power from the battery is allowed to go from positive to negative without slowing down to do something.... (i.e. light up a bulb).

Too much power will follow that path and burn things.

It SHOULD HAVE BURNED THE FUSIBLE LINK you don't have. Burning the wire to the ammeter is a fire risk.

If you have blown fuses, it's probably an issue in the harness between the fuse and the load.. (short would be in the wire before the bulb / fan / etc...).

But it could be a bad fan, bulb, etc., or a bunch of other issues.... AND... All that green is copper corrosion which creates resistance which creates heat... Those connections need to be clean.

 

[45Dougal]

Check volts again at fuse panel - some are working it seems but some not - maybe corroded or blown.

Check your ignition switch connector now under the steering wheel. Open it and clean it out

 

[tls3601]

You need to check the FUSIBLE LINK as has been mentioned three times!
The fusible link connects to the positive battery terminal. It's job is to protect the charging circuit 10ga wires.
Here is the path this takes: From battery + through the fusible link, into the solid white 10ga wire coming out of the main harness near the battery, and routes to the Amp Meter + terminal. Then through the Amp Meter, out the - Amp Meter terminal where it turns into a 10ga White/Blue wire and goes to the alternator B+ terminal.
If your fusible link is bad you will have NO power to the fuse panel. Also if your Amp Meter is bad your battery will not charge as that circuit will be open. You can just short to two Amp Meter wires together to get going.
I sell new fusible link kits that include the fusible link, the battery side connector and a new harness connector and terminal. Click on the link in my sig line to go to my web site.

View attachment 3468578

Pretty sure I am going to need a fusible link for my 3/76 FJ40 but could not find your website. Have a link? Thanks. Tom

 

[GA Architect]

Pretty sure I am going to need a fusible link for my 3/76 FJ40 but could not find your website. Have a link? Thanks. Tom

Here ya go < click here >

 

[pb4ugo]

Pretty sure I am going to need a fusible link for my 3/76 FJ40 but could not find your website. Have a link? Thanks. Tom

If you're viewing this site with your phone vertical, turn it sideways and look at the bottom of Coolermans post. The link to his website is in his signature at the bottom of his post.

 

[tls3601]

Here ya go < click here >

Thanks Rick. Thinking of ordering two, same part number as my 10/78. How was your Christmas down there in Georgia buddy?

 

[tls3601]

If you're viewing this site with your phone vertical, turn it sideways and look at the bottom of Coolermans post. The link to his website is in his signature at the bottom of his post.

@pb4ugo much appreciate sir! Yes always checking things out with a phone, side orientation is the ticket! Hope you had a great Christmas