Where do these plugs go? (wire harness) (1 Viewer)

Kent

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Sorting out the usual hacked up cruiser and I am trying to clean and repair the harness. The engine bay is stripped of all electrical parts. Some of the wires have bare spots and need replaced. Some of the ends look to me like they may not be factory original. I pulled all the black electrical tape to inspect the wires and sort things out.

Can someone please label which device these plugs go to? This is a 76 FJ40 and this is the passenger side harness that comes through the firewall near the vent motor.

I did not include the plug going to the vent motor as I figured that one out.

I think L goes to the positive battery terminal clamp?

M is the plug from the vent motor.

I think N goes to the distributor?

I think R and S go to the rear light harness?

Thanks!!!

Wireharness.jpg


wireharness2.jpg


Wireharness3.jpg


wireharness4.jpg
 
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I'd ditch the whole mess and go with a EZ-WIRE OR QUICK-WIRE and be done with the old stressed-out factory harness scenario................
 
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Enumclaw Plateau
All of that looks very familiar to me but I'm at work so will have to compare when I get home and can look at mine....but, I believe

E and F got to front turn signal

D is the headlight

A might be the horn ( one on each side of the radiator)

B battery positive ?

I ground to the frame ( make sure you get a good clean ground)

The rest I'll need to check when I get home
 
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D-looks like headlight, A- looks like horn, B-if it has a big white goes to the alt, F&E look like clearance lights,LorK voltage reg., , u-heater fan and R-S go to rear harness..... EDIT...wow posted at same time
 

Kent

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I hate to ditch the whole thing as it looks to be in good shape, just some spots that need TLC. If I can figure out where it all goes I think I will have it whipped. Most of it was covered in oily mud so the wire insulation is still soft and flexible. There were some weird things done to this rig before I got it but most of the wiring seems to be ok.

Now I am doing weird things to it myself :hillbilly:

Thanks for helping me piece her back together :)
 
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Specter's year-specific wiring photocopies usually come with both a schematic and a diagram for the mid/late 70's cruisers. The difference being that the schematic is all in engineer speak and not to scale and the diagram portion shows the actual harness with accurate depictions of the shape of the connectors, which wires terminate in which hole, and where each one is in approximate relation to the vehicle in question. They've made things much easier with more than one vehicle I've dealt with.
 

Trollhole

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Sorting out the usual hacked up cruiser and I am trying to clean and repair the harness. The engine bay is stripped of all electrical parts. Some of the wires have bare spots and need replaced. Some of the ends look to me like they may not be factory original. I pulled all the black electrical tape to inspect the wires and sort things out.

Can someone please label which device these plugs go to? This is a 76 FJ40 and this is the passenger side harness that comes through the firewall near the vent motor.

I did not include the plug going to the vent motor as I figured that one out.

I think L goes to the positive battery terminal clamp?

M is the plug from the vent motor.

I think N goes to the distributor?

I think R and S go to the rear light harness?

Thanks!!!

Wireharness.jpg


wireharness2.jpg


Wireharness3.jpg


wireharness4.jpg

Off my head.

A= horn

B= Alt

C= Alt

D= headlight

E= Marker light

F= Marker light

G= coil ground (if it's a white black wire)(if it's red no idea)

H= coil ground (if it's a white black wire)(if it's red no idea)

I= 12V+ Coil

J= ballast resistor bypass goes from coil to starter

K= horn relay

L= 12V+ battery (connects to fuseable link)

M= heater blower

O= starter (comes from the wire on coil to starter)

P

Q

R= rear harness

S= rear harness

T

U

That's all I can remember
 

Coolerman

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Kent,
If you need some correctly striped GXL wire or some connectors and terminals to repair your harness I may be able to help. Visit my wiring site in my sig line then send me an email telling me what you need. I can also make up sections of harness and crimp the ends on for you if you need them.

I have found that if a harness has not been too abused it is MUCH easier to repair it than try to go the EZ or Painless route. If it is too far gone then a used replacement is often the cheapest and fastest way to get going again.
 
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Alright another guessing game.. sounds like you will be posting later with elictrical gremlins.
I would find someone with another LC same year as yours and mix and match with what the other has.
 

Kent

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South Dakota
Thanks guys!

I knew someone (actually a lot of you) could rattle these off in 5 minutes. I looked at the schematic and I can "kind of" understand it. Trollhole I appreciate you taking the time to solve it for me!

Coolerman - there is one wire that looks like it may need your assistance. It is broken and down to bare wire right at the plug. It is L, the one that goes to the battery by way of the fused link.

Info like this would be helpful in the FAQ if we had pics up of all the wire harnesses (I know it would be a large amount of info with all the different years) and labeled as to where the harness plugs go. I see a lot of people with open plugs and wires and I would have no idea if it is to something slightly important or if it is something no longer on the truck (such as a trail rig with no horn or turn signals).

When I see connectors blowing in the breeze on my 40 I get an uneasy feeling of gee do I need to hook that to something. If so what am I missing?


If people think it is worth it, I would do the same as above with the entire harness for a 76 40 and post it in one thread for reference. I will need a lot of help with IDing the correct plug locations though.

Is there any value to others in doing this? If not I will go back to garage and keep working on my project and find more questions for you guys :)
 

Coolerman

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I is a large BY wire and goes to one end of the ballast resistor. There should be a pigtail off that wire with a female bullet connector that goes to the igniter.
N is the red distributor wire. It's other end is H or G, looks like H and G are spliced? Which ever is spliced to red that wire goes to the igniter.
I believe O is the starter solenoid wire from the key switch it is the larger of the two BW wires there
P is the other end of J and is the ballast bypass and is a smaller BW wire. It connects to the + side of the coil.
If Q is a YB wire then it is the oil pressure sender unit wire.

I based this on 1976 schematics and I have a complete 76 harness laid out on a board right now... I have some pics of this area it you want to see what it should look like.
 

Kent

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Thanks Coolerman,

P and Q are twisted together right after the plug on P. So is it correct that the oil pressure sender (Q) is getting power from P (+ side of coil)?

At first glance I wouldn't expect those to be connected. I would expect Q to be taking info from the oil pressure sender back to the cab (the guage). So do I understand correctly that it is powering the sender and there is another wire sending the info back to the guage? The oil pressure sender is then acting as a resistor that the guage in the dash is translating to a psi for the driver to make sense of.

I have a pretty good grasp of the mechanical workings of this truck, but the electrical is :eek: for me.
 

Coolerman

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Remember J connects to the starter. When the starter is engaged this wire will have +12V on it. The other end of J is P. P connects to the +side of the coil. So... when the starter is engaged the + side of the coil will get the full +12 instead of the 9 volts it usually gets from the ballast resistor. This helps the truck start when cold. Now since Q is tied to P it will also get +12V but ONLY when the starter is engaged. Don't know why the PO did that one... The oil pressure sender wire should be yellow/black. Maybe it's taped up?

The sender GROUNDS the Yellow/Black wire through it's body via an internal resistance that gets lower as the oil pressure gets higher. As this resistance varies due to oil pressure changes the gauge value changes.
 

Kent

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Coolerman,

Thanks for hanging in on this one with me! I double checked the harness and Q is in deed spliced into P. P is a small black and white wire. Q is a solid dark brown, gray or faded black color.

The oil pressure sending unit is on the block on the driver side correct? How does this passenger side harness tie into that unit? I don't think it will physically reach so what am I missing as I try to make sense of this in my mind.

Thanks again

Kent
 

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