FJ40 Wire Harness Reference - December 1978

woytovich

Science...
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Well, in my project to reassemble my 40 from a few other 40s I decided to use this 12/78 harness... I hope that these pictures, along with an identifying list, will be useful to some of you.

Here is the picture. As you'll see each item is numbered... I would like to create a table cross referencing the numbers with their application and additional details. The table will get posted here and updated as needed. I will be asking for help from the experts out there.

Here is a large version of the below image (1.3mb):
https://forum.ih8mud.com/media/12-78-fj40-harness.51835/full?d=1487176137

Here is a stupid large version:
WireHarness12_78_lrg.jpg

HERE IS A LINK TO THE GOOGLE SPREADSHEET. If you have the knowledge, PLEASE update the spreadsheet!

Spreadsheet


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NOTE: there is a September 1976 harness reference posted here:

FJ40 Wire Harness Reference - September 1976

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WireHarness12_78_vsm.jpg



SCROLL DOWN FOR REAR HARNESS INFO
 
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Jan 25, 2007
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3,955
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Lincoln, CA
1. Alternator
2. Alternator
3. Distributor?
4. Coil?
5. Passenger Horn
6. Wiper Motor
7. Passenger Headlight
8. Passenger Turnsignal
9. + Battery Terminal (Pictured is actually not stock - there should be a fusible link here to connect to the main harness)
10. Starter motor
11. Oil Pressure Sender
12. Coil?
13. Starter
14. Heater Blower
15. ??
Hose Wiper Bottle
16/17. Rear Harness Connections
18. Voltage Regulator
19. Carb Cooling fan Relay
20. Seat Belt Buzzer/Relay
21. Fuse for Carb Cooling Fan Relay
22/23. Wiper Motor Harness Connections
24/25. Plug socket in the Glovebox
26/27. Dash Pad Light
28/35. cigarette Lighter
29. Some Switch - Wiper Motor Switch?
30/31. Wiper Motor Harness Connections
32. Rear Heater Wire Harness
33. Fan Switch?
34. Cooling Temp Sender Switch and ???
35. see 28
36. Hazards?
37. Parking Brake switch?
38/39. Light for Heater Controls Mounted under dash
40. ??
41. Brake Switch?
42. ??
43. Steering Wheel Harness
44. Steering Wheel Harness
45. Alternator Gauge
46. Alt Gauge
47. Dash Cluster
48. ??
49. ??
50. ??
51. Flasher relay?
52. headlight swtich bulb
53. Headlight switch
54. fuse box
55. ground
56. computer
57. carb?
58. carb?
Somewhere around here are the brake pressure switches for the master cylinder.. i don't see them in your harness maybe 59 and 60? ALso carb cooling fan sensor wire needs to be around here somwhere
59. ??
60. ??
61. Ground
62. ???
63. Emissions(VSV)
64. Driver Turn Signal
65. Driver Horn
66. Driver Headlight





i tried to do this from memory.. honestly it should be obvious what the rest is... i have multiple wires not hooked up on my 78 - i don't know what they could be and don't have any issues.. fyi
 
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Can anyone help finish up the spreadsheet?

Thanks for doing this. I have a December 78 40. This will be very helpful when it comes to reassembly.

My engine is out and the frame is off but I haven't taken the wiring out of the tub yet. I'll see what I can do tomorrow to verify and add to the spreadsheet.
 

woytovich

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Rear harness reference

Here is the rear harness part... Please assist by posting here and/or to the linked spreadsheet (see 1st post.)

rearHarness12_78_LG.jpg


12_78_rearHarnessSM.jpg
 
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Asheville NC
I'm in the process right now putting my old harness back in.
Once you start putting the wiring back in the cruiser you will be able to see where each connector goes.
If you have a problem finding out where a connector goes look at the Factory wiring diagram and it will tell you what it does.
You have to have LOTS of patience!! I started out trying to put in a brand new aftermarket wiring harness in and at the same time put in a wiring harness from a 3FE motor... spent 8 days straight on it before deciding that the old harness was still better than a new one..

Get some music going and just start at the fuse box..
 

woytovich

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Channeling the dudes at the Toyota Wiring Department certainly helps, there is a rhyme to their reason for the most part...

I'm hoping that a reference like this will help speed that process. So... anything you can add to the spreadsheet would be appreciated.
 
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What number is the Radio? I can't open the spreadsheet since it picks up I have an google account or something. Anyone know?
 
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Rear Harness

101 - Underhood main connection on firewall
102 - Underhood main connection on firewall
103 - Unused
104 - Unused
105 - Reverse light switch on trans
106 - 4th gear position switch (Not used on 79?)
107 - 4th gear position switch (Not used on 79?)
108 - Frame ground
109 - Fuel tank ground
110 - Fuel tank sending unit
111 - Seat belt warning connection - driver's side
112 - Rear passenger tail light
113 - Rear passenger marker light
114 - Rear license plate illumination (?)
115 - Rear driver marker light
116 - Rear driver tail light

NOTE: The number indicated in the rear harness photo corresponds to my 1978 harness. Mine may not be original.
 
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If the tag on 15 is correct and it connects to the starter then i think 13 should be the Ground wire from the Coil which connects to the side of the Distributor.

Or its the other way around, 15 - Distributor, 13 - Starter.

Travis.
 

shipmag

Hagler Technology LLC. Aka Shipmag
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Does any one have a complete pic of main and rear harness with numbers and the corresponding spread sheet filled out completely. I need one for a 8/76. Thanks IT would help to give me a file or link where I can down load it in a readable format my old eyes would be able to see.
 

Coolerman

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I posted at the beginning of this thread that I would eventually get around to documenting every circuit of the 1978 harness. That day has come!
I finished this up recently and just finished updating the Goggle spreadsheet to reflect my tracing out every circuit in both the main and the rear chassis harness. I learned many things about the 78 harness. First, it is completely different from the 76-77 harness. Toyota changed many things on this harness.

Second the harness I documented has the mythical Yazaki Resistance wire embedded in the harness. I had heard of this but had never actually seen it. It is a 12 ga pink wire exactly 63 inches long running from the fuse panel area in the main harness to about where the rear chassis harness plugs are located. This wire is in series with the key switched BY 12 ga coil power wire. Its purpose is to replace the ballast resistor for the coil. I used my Fluke 87 meter to measure the resistance and it was exactly 1.2 ohms, just what a ballast resistor would measure. Still don't know why they thought this was a better idea than just using a resistor.

Third: This harness is full of connector types that are no longer available, even from Toyota so building a new harness with OEM connectors isn't going to happen. :(

Anyway, I know I don't get here often anymore, but if you have a question about the actual circuits in a 78 harness I can probably answer them now. email or pm me...
 

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