1975 FJ40 Instrument Panel Not Working

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So, I got 2 clusters and tried both of them and still nothing. The Amps work, but still nothing else. When I redid the wiring, the wires going into the Lights Switch were burnt too. Is it possible that the light switch needs to be replaced? Maybe the circuit was fried and I need the light switch to work to provide power to the instrument cluster?
 
Ok...bump to an old thread that I never fixed. I did a bunch of other work to the truck and now have it driveable so I need to figure out this electrical. Here is where it stands...when I turn the key to 'on' nothing works...I have power to the LR and WL wires, but no power to BW or BY...I think that is supposed to be that way. I have power to all the fuses...I have a new speedo and light switch (new used).

When I start the engine, I get power to BW and BY from the ignition on the steering wheel. When I turn the lights on (first indent) I get front parking/turn lights, rear running lights on the side rear quarter panel, and middle lights in the brake/turn/reverse...but no brake light when I step on the brake. I also get a light in the speedo. Turn signal and reverse lights don't work.

Heater blower doesn't work, hazards lights don't work and neither do the wipers. I think the Amps in the speedo work (with truck running it's drawing neg amps?). Oil, fuel and temp no workie.

At this point, I don't exactly know where to start. I do have a couple wires between the brake lights that aren't connected to anything...and a couple other random wires under the body about mid vehicle that aren't connected, but need to trace those.

Pictures attached are a couple wires in the engine compartment that are not connected and not sure what they do. The picture with the Red wire...it comes from the Alternator and isn't connected on the other side. The yellow/black wire is connected by me to a yellow wire which I am pretty sure is the oil press wire. And the black/white wire comes from the bundle that leads to the front of the vehicle, but not sure where it's supposed to go, but maybe connect to the ignition coil?

Why does electrical seem like such a pain! Thank you guys in advance for the help.
 
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Alternator is only producing 12 volts. The red wire in pictures 5 and 6 above only has about .75 volts...I would assume the alternator is dead? Voltage regulator is brand new. One other quick note...If I turn the key one position towards start, I don't get anything. I turn one more position and I can hear the fuel pump kick on. Then it starts on the next turn. I think that first position should have something, right?

The only thing that works in the speedo is the ammeter and when the truck is running is always showing a discharge.

I did replace the lightswitch and the tail lights, side rear lights and front parking lights now work. The brake lights, headlights and turn signals still don't work. The horn used to sort of faintly work, but now does not work.

Any guidance? Thank you guys.
 
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I have read through your posts in this thread and looked at the pics you have posted. Here is my initial thought..RUN!!!!! Now that the craziness is out of the way here are my suggestions, they are worth exactly what you have paid for them!!:rofl:

1. Do not assume anything. If you can't prove it with a measurement or observation it didn't happen.
2. Get a correct wiring diagram(s) and print out two copies in color if available. Put one away and mark the other with the VIN of your 40 so you can write on it IN PENCIL ONLY. Annotate this copy with any thing that is different on your vehicle and voltage measurements where you take them. Take really detailed notes.
3. Get a selection of correct size and colors of wire from Coolerman.
4. If you do not know how, learn to properly solder, attach crimp terminals and apply heat shrink tubing using the correct tools. The interweb is your friend.
5. Get a working multimeter, it can be a cheap Harbor Freight special or a NIST traceable Fluke.
6. Having a huge amount of patience and perseverance use the above mentioned wiring diagram(s) and go wire by wire and insure all of them go where they are supposed to go... I didn't say this was going to easy or fun. It will be educational.
7. If you feel the need to put tape on a connection or to leave tape on a connection that you find then :censor:. Not sure on how I feel about using tape? This does not include self-amalgamating tape. You are attempting to fix problems. If you find a taped connection or a bare connection it is a problem, fix it! If you tape a connection you have added a problem.

This should keep you busy for a few hours, just go at a steady pace and be meticulous in your workmanship. Clean all connectors and grounds as you go. Keep things neat, short velcro strips are good for holding wire bundles together while you work on them. Ley us know how you are proggressing.
 
@Cromagnon I was kind of thinking I need to go down that same route...probably start on that today.

Can you help confirm that alternator is no good? And, there are 3 plugs on the alternator, but most wiring diagrams only show 2 wires going into those 3 plugs. I have a red one coming out and leading to nowhere...that's the one in the 5th picture above. Any idea on that one?

So...basically, untape the wire bundle and follow each wire? I can do that...I'll let you know.
 
What does the red wire connect to on the alternator? There are four wires shown, WB, BW, and R going to a connector and WL going to the terminal. If the main wiring harness is from a 75 then the WL goes to the ammeter negative (-) terminal on the instrument cluster, the WB goes to the E terminal on the voltage regulator, and the wire in the N terminal (is that BW?) of the alternator is not connected. If the R wire is in the F terminal of the alternator (should be WG vice R if it is) then that goes to the F terminal of the voltage regulator.
 
WL goes to the ammeter Neg, the BW looks like the same BW wire that goes to the ignition switch (same size wire). The R wire looks like the PO changed it and it's not connected...so I need to make it go to the voltage regulator. I need to follow the WB wire, but I am pretty sure it goes to the Voltage Reg.
I think I need a new alternator with only outputting 12 V with the engine running...I think I read there are 2 options...the Delco or the plug and play (Toyota). It's a 1980 engine on a 1975 rig...is there a better alternator option?
 
If the R wire is on the F terminal of the alternator and it is not connected to the F terminal of the voltage regulator then there will not be an output from the alternator. Hook up the alternator to the voltage regulator and leave the WL wire going to the ammeter. The BW wire should not be connected to the alternator.
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Well...took the tape off to find the WG wire and it's there till just about the alternator (see picture). Looks like he switched the wires in close. He has the WG wire going into a WB wire and the WB wire into the BW wire. Should I switch those around? And in the second picture...not sure which is the E, F and N terminal. In the picture, F is far left, E is on the bottom and N is above E?
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Maybe the PO was freaking colorblind!! If it were me I would correct this vipers nest and put the correct color wire to the correct terminal. WB is always associated with GROUND in an FJ40.

The WB wire should be going to the E terminals on the alternator and the voltage regulator.
The WG wire should be going to the F terminals on the alternator and the voltage regulator.
The WL wire goes from the B terminal of the alternator to the (-) terminal of the ammeter. This seems to be correctly terminated.

With those connections made the alternator should provide an output greater than battery voltage. Something in the range of 13.5 to 14.2 VDC.
 
The R wire into the ground would be a good reason the voltage regulator was fried when I got this thing.

I think I have it wired correctly now...(see picture). Alternator volts are roughly 12 (slightly over at maybe 12.21 on average). I think that alternator is bad. Ammeter still shows discharge and lights now don't work.
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Put the battery on a charger and read thru the FAQs on how to test the voltage regulator to confirm that it is good. That is cheaper than an alternator and easy enough to troubleshoot to rule it out as being bad. Also check the fusible link, I hope it is still there, between the battery and the WL wire. If that is bad you won't see any change in voltage at the battery terminal. There is also a fuse in the fuse panel that goes to the BY wire which is terminated at the voltage regulator IG terminal. Use a multimeter to confirm the fuses are good.
 
Tried to test the VR and when I take the WL wire off the Alternator, then test the BY wire at the VR, there is like .01 volts there with the key on. Then, I start the engine and test the B terminal on the Alternator and there is .45 volts coming off that. The VR is new. I think there is a fusible link to the battery (see picture). If that's not it, then the PO took it off and I need to figure out how to add one in there.

To add to the mess, I pulled duct tape (yes) off the harness going to the fuse box. He has from 1 WL wire, spliced into 2 and connected to the Fuse Box. He did that same ting with the BY wire. Why would he do that? I have looked all over for a picture of how the wiring needs to go in the back of the fuse box...but the wiring diagram doesn't show exact positions of wires. Any help there?
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The picture of the positive battery terminal and small red wire spliced to a small white wire does not look like a fusible link. Do you see B+ voltage on the WL wire? Check at the fuse panel. If yes then there is continuity on the WL wire through the fusible link location. If the fusible link is missing it needs to be reinstalled immediately or there is no circuit protection for the wiring from the battery.

Did you check the fuse going to the BY wire? If this fuse is bad there will be no output from the voltage regulator. When checking fuses and fusible links rely on the multimeter instead of a visual check please.

The WL and BY splice taps look like factory and should be shrink tubed.

If you have the fuse block cover with the fuse name we could make an educated guess as to which wire belongs to which position. Without that it is just follow the color code of the wiring diagram.
 
Probably more than you want to know about voltage regulators HERE.
 
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