Why do I have a brown wire in my stock 73 harness?

[skully3]

I am in the process of redoing a stick harness for my 73. My original one was a mess so i ended up with a pretty clean harness out of a 73 about 500 off my vin. It has a brown wire in the loom looks as if it was done at the factory. Any suggestions

?

 

[BU5H P1G]

perhaps the new harness is a replacement also?

 

[shelfboy1]

i could look in one of my books for the answer but there should be wiring harness diagrams on this site .they will guide you through the process of rewiring your truck i have seen that wire before but just cant remember where it goes .good luck

 

[Coolerman]

If the brown wire is in the rear chassis harness that is probably OEM. Sometime in 73-74 Toyota starting using wire colors like pink,brown,white, red and black in the rear chassis harness. Don't know why. Maybe they had a surplus of those colors left over from one of their other car lines.
I have never seen a schematic that had those colors.

 

[skully3]

If the brown wire is in the rear chassis harness that is probably OEM. Sometime in 73-74 Toyota starting using wire colors like pink,brown,white, red and black in the rear chassis harness. Don't know why. Maybe they had a surplus of those colors left over from one of their other car lines.
I have never seen a schematic that had those colors.

It was definitely factory but the the other odd thing was a solid black wire started at the splice by the alternator regulator and went out to the alt plug and headlight. The wire was w/b before.

But since i have ur attention coolerman, u think you could help me identify some of the wires in the pic below. Also i could use some loom wrap you sell. I know the top three go out thru the firewall to temp sensor and carb. But how do i fix up the heater wire, and what are the r/g r/w wires? Thanks in advance. .

 

[Coolerman]

Schematic Color codes for FJ40 wiring:
B = Black
L = Blue
O = Orange
Y = Yellow
R = Red
W = White
G = Green

Any two letters means Base color then stripe color so LY would be a blue wire with yellow stripe. BR would be Black with Red stripe.

Non-Standard FJ40 colors used in rear chassis wiring mainly
Br = Brown (not a normal color)
Pk = Pink
V = Violet

When making notes about wiring it is VERY easy to write B for blue instead of L ... just be aware of it...

I think your harness was modified by a PO or by a shop that did a good job taping it back up. I have never seen ANY other colors beside WR(switched + to regulator), WG (field control from Regulator to Alternator) and WL( B+ from alt to Amp Meter) in the alternator/regulator circuit.

Take a pic of that section where it is spliced together. The very fact that it is spliced tells me it's been worked on.

As for your other questions about the wires.
RW is normally lighting or Brake switch related
RG is the dome light

 

[skully3]

You were right, i followed the black wire to a repair to the headlight. I will strip that section out of my old harness and repair it.

 

[Coolerman]

Yes, they spliced a block wire into the White/Black ground circuit. I have the WB16 ga wire and the headlight socket terminal if you want to fix it correctly.

 

[skully3]

Thank you, I am going to email you for some other things, I fixed this already by robbing it out of my other harness. I found the schematic on your site that was (the same from the hynes manual 72/73) almost spot on. When I'm done I plan on documenting the harness the way wytovich did for the 78 harness. I think it will help some folks who don't care to get into the details. I also plan on doing a build thread once I can commit fully.

 

[Coolerman]

I have a 72 harness I bought off E-Bay that I am going through for learning/documention purposes. It is in good shape just missing a lot of under hood wires like the temp and oil pressure wires. I am restoring it as I go. One thing I would like you to do: Can you take a pic of the gauge cluster harness? The early (pre-71) gauge cluster harness used two 4 pin plugs but the 72 seems to only use a single 6 pin plug? A pic of the back of the cluster and a close up of the plug would be great!

 

[skully3]

Lmk if you would like any other pics. Id be happy to help.

 

[bertsulli]

From my 9/72...very dirty but hopefully helpful.


I have some close ups as well.

 

[FluByU]

I am going to be doing this in the next several months. Thanks for all the documentation to help the rest of us out.

 

[Coolerman]

Awesome! That answers the question about the cluster connector type. 72 harnesses are strange...

 

[skully3]

maybe someone can chime in here and help me finish this up. This picture is for end point reference only and does not get into specifics, but it will help people identify where everything on the 72/73 harness goes. if something is out of place please lmk...

.

 

[Coolerman]

The wire top left, next to the VSV Valve, is probably the low brake pressure switch wires. What color is it?
The other I have no idea though I can look tonight to see.

 

[bj40green]

Awesome! That answers the question about the cluster connector type. 72 harnesses are strange...

Yes, 1972 was a change over year. Look at the differences between these two clusters.
March 1969 - Sept. 1972 (2nd gen.)

Sept. 1972 - Sept. 1973 (change over to 3rd gen.)

The inside of this cluster is 3rd generation but the housing is still 2nd generation.
Note that the turn indicator lights are already in the speedo housing and that the FUEL gauge is the 3rd gen. model with the 3rd stud for the internal voltage regulator.

Sept. 1973 - Dec. 1978 (3rd gen.)

More info on clusters and gauges here -► https://forum.ih8mud.com/threads/clusters-gauges-speedo-odo-meters.544543/

Rudi

 

[skully3]

https://forum.ih8mud.com/threads/wiring-harness-connector-id.701993/
Its seems this has come up before....like most things that are 40 years old.

Here is a finished pic...

 

[mudpaws]

wow you guys are getting into the core details, love it! Hey, I wonder if Mark W's '78 has any of my former '77 harness or other parts on it!

 

[DSRTRDR]

the break pressure switch wire should split into two ends - for each cylinder on the brake master