Wiring Diagram 76 FJ40 (1 Viewer)

[lkortbeek]

I am trying to rewire a 76 FJ40 and am having a few problems. I have been trying to work off the 78 diagram I downloaded from the tech page and the 79 I have from my FSM. The 78 is closer but I am still having issues, particularly with the alternator and voltage regulator. I would rather not pull the whole thing and start from scratch (although it seems tempting). Anyone have a copy of the 76 wiring they can flip me?

 

[Pin_Head]

Sorry, no '76 schematic, but the alternator and VR wiring on my '76 is exactly like that shown in the '78 schematic diagram.

 

[lkortbeek]

Ok then I am obviously missing something. My VR has 3 wires coming off it that make sense to me, W/B (I assume this is the ground from the wiring diagram), a B/W and a B/Y. The B/Y is supposed to go to the Alt (I think). At the Alt, I have 2 pigtails, A three pin one that fits in the back of my Alt and a 6 pin with 4 wires. The three pin has a R/W, G/W and G. The 6 pin has a B/Y (which has continuity to my VR) a L/R, L/Y and L/B. Any pointers before I start cuting?

 

[Pin_Head]

That is a lot of wires for an alternator and VR. Are you sure it is a stock Toyota alternator? The alternator only has two wires from the VR:

White/green stripe that energizes the field coil (F terminal of alt).
White/black, which is a redundant ground wire to make surethat the alternator and VR "see" the same ground potential.

There is also a large white wire with light blue stripe from the B lug (power output) of the alternator that connects to the - side of the amp meter.
That is all.

The VR gets power from the engine fuse via a black wire with yellow stripe.

Even the later internally regulated alternators don't use that many wires.

Pictures might help.

 

[lkortbeek]

I forgot to add the white with blue, which is there. That wire comes off the alternator but for some reason there is nothing in the harness to attach to. It almost appears to be a separate wire that needs to run along the Firewall to the passenger side where I have a W/B with nothing to attach to (as only a pure white should attach to the battery through the fusible link).
The alternator is stock and the 3 wire pig tail fits it perfectly - its just the wire colors do not add up. I will try and post some pictures tonight. It looks like rewiring is sounding better all the time - at least then I know what I have!

 

[thecrazygreek]

Your VR should have 3 wires coming off of it along with a pigtail wire that provides power to your vacuum system. The 3 wires all "should" be in a plug that simply plugs into your harness. Your alt should have only 3 wires coming off of it. I have a 76 and this is teh way mine is set up. My haynes manual provides the 76 diagram as well.

 

[Pin_Head]

I forgot to add the white with blue, which is there. That wire comes off the alternator but for some reason there is nothing in the harness to attach to. It almost appears to be a separate wire that needs to run along the Firewall to the passenger side where I have a W/B with nothing to attach to (as only a pure white should attach to the battery through the fusible link).
The alternator is stock and the 3 wire pig tail fits it perfectly - its just the wire colors do not add up. I will try and post some pictures tonight. It looks like rewiring is sounding better all the time - at least then I know what I have!

The W/B wire from the alternator passes through the firewall where it connects to the amp meter - post. The white wire from the fusible link and battery also passes through the firewall and connects to the + post of the amp meter. That way all of the current in and out of the battery (with the exception of the starter motor) passes through the amp meter.

 

[lkortbeek]

OK, the harness off the VR makes sense. Here is a picture of what I have. At least now I know what the spare plug is for.
Here is a picture of the harness coming to the alternator. The 3 wire pigtail plugs into the alt like it belongs. The problem remains that the b/y wire I expected to have there goes to the 6pin plug instead. I do not have a large guage wire going to the ammeter on the driver's side of the firewall, but I do have it coming out the pass side. I think I'll strip the harness back to ammeter and make sure that it is the wire it is supposed to be. Anything familiar with the harness to the alt? I hope the pic'ts load as I haven't done that before...

 

[Pin_Head]

Those color wires go to the brake switch. Even though the alt has 3 prongs, only two are used: White green wire goes to the F terminal and white black (ground) goes to the E terminal. You can see these wires coming off of the VR, so just follow them to the correct plug.

 

[lkortbeek]

Thanks for your help. My problem was that it looked too good to be true (and it was...). The wires from the VR go back into the loom under the dash making it harder to trace. I have a couple of other mysteries that don't match the wiring diagram either so I guess it is strip and trace time.

Again thanks for your input!

 

[cruiserbrett]

your alternator plug is the one hanging by the shock tower.

I am a little perplexed by the fact that there is a later plug in the wiring harness. Those round waterproof connectors didnt show up until 78 or so in the states. Maybe different for CA cruisers though...

Also, on US spec 2F's the alternator was on the passenger side... which might explain why the 10 ga w/b wire is there.

 

[Pin_Head]

I have a couple of other mysteries that don't match the wiring diagram either so I guess it is strip and trace time.

Again thanks for your input!

There is no need to strip the wrap off the harness to find the other end of the wires. I guarantee that you will find the other end emerging somewhere and you can confirm its continuity with an ohm meter with the ends disconnected.

The correct plug is part of the short pig tail leads that is hanging by the shock tower, but it appears that this plugs into another connector.

 

[lkortbeek]

Actually the alternator is from a 78 so that explains the plug. Talk about a Eureka moment. Obviously (now at least) the three pin connector with the two wires should fit into the alternator. I just need to find the corresponding wires on the loom. Knowing that they may be on the passenger side helps a lot, and explains why the main wire (W/L) is on that side. I'll look for the other wires there.
Suddenly it starts to make sense.
The 6 pin is probably emissions control related then as the wire colors match up. Funny how perspective makes a big difference!

 

[lkortbeek]

After my last post last night I decided I needed to check the entire harness anyway and pulled it from my truck. I found a couple of not so good splices in the process so I am glad I did it. Knowing where to look of course also helped tremendously, and I found the "other" wires going to the alt in seconds flat! Thanks for all the help as this one had me stumped. Back to taking nothing for granted.