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Early Model Engine-to-Main wiring harness question
Posted by: OldWrenchTurner ()
Date: April 25, 2022 06:52PM

Hi everyone,

I'm repairing the main wiring harness where it enters the engine compartment and plugs into the engine wiring harness. The plug from the main wiring harness was cut off by one of the previous owners and a (badly) fabricated engine harness was put together to accommodate some mods they installed. The whole mess was then hard wired together (engine and main).

I now have a bright shiny new engine harness from Clark's with the correct plug and I am in the process of repairing the main harness by attaching the correct plug to the end in the engine compartment allowing it to connect with the Clark's harness.

The wiring diagrams in the Shop Manual and Assembly Manual show exactly how the wires are supposed to be laid out for the plugs. There are 8 connections total on the plug(s):

Large (10ga.) black wire - main lead
*Normal (20ga.) brown wire - 'A' terminal on voltage regulator
Normal (20ga.) black wire - tail lights and plate lamp
*Normal (20ga.) brown or yellow or white wire - coil
Normal (20ga.) dark blue wire - oil pressure and temp switches
Normal (20ga.) purple wire - right hand directional signal
Normal (20ga.) light green wire - back-up lights
Normal (20ga.) pink wire left hand directional signal

The question I have concerns the two 'brown' wires (* above). According to the shop manual, the second 'brown' wire is supposed to be yellow. However, the assembly manual says it's brown. The plug position on the Clark's harness has a white wire. In my car, I have two brown wires - all the rest of the colored wires correspond to the wiring diagrams in the manuals.

Like a big dummy, I cut out the garbage old wiring harness and didn't label any of the wires near the plug end. Now I don't know which brown wire is for the 'A' terminal and which brown wire is for the coil. I've looked at where the main harness comes into the passenger compartment for a clue, but the wiring is split here into two plugs which both have all the colored wires above making a very confusing situation.

I'm hoping someone here might know which brown wire is which based on its physical location in the main harness as it comes into the engine compartment.

The main harness has a 'sub' harness taped together. It contains five wires - the purple, light green, pink, normal black, and brown wires. Separate from those, the large black, dark blue and other brown wire are taped on top of this 'sub' harness.

So is the 'A' terminal brown wire the one inside the 'sub' harness? Or is that the coil brown wire?

Thanks for any help you can give me! thumbs up



Edited 1 time(s). Last edit at 04/25/2022 06:56PM by OldWrenchTurner.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: MattNall ()
Date: April 25, 2022 07:46PM

DaleUse your meter for continuity

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Re: Early Model Engine-to-Main wiring harness question
Posted by: solo2r ()
Date: April 25, 2022 08:14PM

You can just hook up the B+ to the body connector and then turn key on to determine which is the coil wire + and can even check all the wires...turn , brake, tail! and even the gen/ fan and temp/ press lights



Edited 1 time(s). Last edit at 04/25/2022 08:16PM by solo2r.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: JimBrandberg ()
Date: April 26, 2022 04:44AM

Sometimes I take a jumper wire from the battery + to feed into the system in order to see where it shows up.
The wire colors in replacement wiring harnesses are often not correct.
The stock wire colors sometimes changed between years. Often but I suppose not always, the position of those wires in the multi-connectors stayed in the same place.
It sounds like you're systematically making your own diagram and figuring it out.
I quit smoking 32 years ago. The only time I get the urge is when having electrical problems and studying an electrical system diagram.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Early Model Engine-to-Main wiring harness question
Posted by: Lane66m ()
Date: April 26, 2022 05:25AM

Tell us your EM year. My shop manual for 61-63 shows R/W/B going to coil. No 2 brown wires to connector


Ohm meter on coil wire at coil. Check which wire at engine connector location has continuity. Put it in the correct plug position.

Ohm meter on VR connector brown wire. Check which wire at engine connector location has continuity. Put it in the correct plug position.

Attachments:
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Re: Early Model Engine-to-Main wiring harness question
Posted by: OldWrenchTurner ()
Date: April 26, 2022 07:50AM

Thanks for the info guys. Guess I left out some important information. Like the fact that the interior wiring has been removed (lol) - this is the current state my dash is in on my 61 sedan.



So I really can't check continuity at the ignition switch (that's why I alluded to the 'two plugs' at the end of the main harness that comes into the passenger compartment in my first post).

Below is the end of the main wiring harness as it comes into the engine compartment in its current state. As you can see, it has all the correct colors for a 61 according to the assembly manual. But the two brown wires are the ones I messed up not labeling when I removed the old junk harness. Looking at the picture does anyone know from the physical locations which is which? (To me being a layman, I would assume the engineers would have put the 'A' terminal regulator wire as the 'other' (outside) wire since it was plumbed in the harness with the 'main lead' (large black) wire which both go to the voltage regulator. But I could be completely wrong - the blue oil idiot light wire is there too!)





Edited 1 time(s). Last edit at 04/26/2022 07:52AM by OldWrenchTurner.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: Lane66m ()
Date: April 26, 2022 08:16AM

I can't see anywhere in 61 shop manual that 2 brown wires are in the body harness. You may have to change that body harness, so it matches factory.

I have that same Edward Scissorhands work on my Camaro. I had to replace all harnesses, just to get a good understanding of the wiring and to make things work right.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: OldWrenchTurner ()
Date: April 26, 2022 11:17AM

Lane66m Wrote:
-------------------------------------------------------
> I can't see anywhere in 61 shop manual that 2 brown wires are in the body harness. You may have to change that body harness, so it matches factory.
>
> I have that same Edward Scissorhands work on my Camaro. I had to replace all harnesses, just to get a good understanding of the wiring and to make things work right.


Yeah, the shop manual shows a yellow colored wire in the diagrams for the coil. The assembly manual shows a brown colored wire (which is what I have). The new engine harness that I got from Clark's has a white wire that is the plug mate for the yellow or brown main harness wire shown on the diagrams just to add more confusion. And to add to that - there is a separate yellow wire on the Clarks harness that goes to the starter from the coil - lol!

I know the main harness is original to the car. I just need to figure out which brown wire is for the coil and which one is for the 'A' terminal on the regulator so I can rebuild the end plug.

I only wish the folks who did the original mods hadn't cut out the original harness plugs. It would have made thing s so much simpler. Well that, and I should have labeled the wires near the mod splices before cutting out the garbage harness work.sad smiley

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Re: Early Model Engine-to-Main wiring harness question
Posted by: joelsplace ()
Date: April 26, 2022 11:22AM

Isn't that the wire for the light in the instrument panel? Use a meter to see which brown wire is connected to that light socket.

Joel
Northlake, TX
5 Ultravans, 135 Corvairs and counting...

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Re: Early Model Engine-to-Main wiring harness question
Posted by: oldqmguy ()
Date: April 26, 2022 02:38PM

Looking over the "updated diagram" for 1960 to 1964 Corvairs in "The Classic Corvair, 8th Edition" by the late Bob Helt I see the following wires coming from the FRONT to the Engine Compartment (the MAIN Harness):

1 20 P Left Stop/Turn Light
2 20 V Right Stop/Turn Light
3 20 BRN Gen/Fan Light
4 20 DBL Temp/Pressure Light
5 18 BRN Ignition ON +12V
6 20 B Tail/License Plate Lights
7 20 DG Engine Overheat (TC Only)
8 20 B Head Temp Gauge (TC Only)
9 12 V Starter START +12 V
10 10 B +12 V to Fuse Block
11 20 LG Backup Lights
12 14 BRN Heater Fan Motor

First number is just to identify the cable.
Second number is the AWG of the Wire.

So according to Bob, there are 3 BROWN WIRES in the Main Harness!

I hope this helps!

Dale cool smiley

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Early Model Engine-to-Main wiring harness question
Posted by: Lane66m ()
Date: April 26, 2022 03:16PM

Heater fan wire exits before harness coming into the engine compartment.

But take a look at the 61 shop manual to see what GM shows for wires entering the engine compartment for the 61 Vair. Maybe someone has a good wiring diagram for a 61 that corrects any GM shop manual errors.

Better if someone has a 61 and can take a photo of both sides of the factory engine harness with body harness connected.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: OldWrenchTurner ()
Date: April 30, 2022 06:19PM

Thanks everyone for the assist. smiling smiley

I finally had time to figure out which wire is which on the interior plug side of the main harness (that plugs into the instrument panel harness). And with that I thought I was done....

Well apparently I'm not, and now more confused. lol.

Here's where the wires end up on the interior part of the main harness:



And here is where the confusion comes in - the wiring diagram shows two colored wires in the SAME location to this plug. Both of these are the circuits I am trying to identify! The main harness 'A' regulator circuit (brown wire) and the main harness coil circuit (brown wire). Also, sorry the diagram wire location is a little confusing compared to the actual plugs. The second from the right brown wire in the first picture corresponds to the second from the bottom brown wire in the plug diagrams.





Here is the instrument panel plug that plugs into the main harness (first picture above).



As you can see the 'sub-harness' brown wire in the main harness swaps to green in the instrument panel harness. This makes me assume that the 'sub-harness' brown wire is the coil/ignition circuit (see second diagram above) and the other brown wire is the 'A' regulator circuit.

The diagrams showing two different colored wires at the same plug location is what is throwing me off here. Am I just over thinking it?

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Re: Early Model Engine-to-Main wiring harness question
Posted by: junkman ()
Date: April 30, 2022 06:39PM

You will probably be better off just buying all new harnesses because the old wires might just let the smoke out of the insulation causing you more grief than you bargained for.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: Lane66m ()
Date: April 30, 2022 06:55PM

I think confusion is evident. But in 2nd wiring diagram, upper connector is the instrument panel connector. The lower connector is body harness to fuse box harness.

Someone else will need to confirm my observation of the diagram.

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Re: Early Model Engine-to-Main wiring harness question
Posted by: Frank DuVal ()
Date: April 30, 2022 08:54PM

Quote
Dale
1 20 P Left Stop/Turn Light
2 20 V Right Stop/Turn Light
3 20 BRN Gen/Fan Light

P=V? Power = Voltage, wait, that's not what I meant. Purple is not Violet? I see Purple wires in most Corvair harnesses, never seen a Violet growing there.grinning smiley

But then Violet goes......grinning smiley You have to be over 50 to know what that is about. winking smiley

Now to be serious, make a long lead for your DMM, add an alligator clip (not a crocodile clip) to this lead. Connect the alligator clip to one brown wire in the engine bay, use the DMM and the short lead to backprobe the connectors under the dash. This will at least get you to the right connector, and from there maybe know what the wire does.

Frank DuVal

Fredericksburg, VA

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Re: Early Model Engine-to-Main wiring harness question
Posted by: oldqmguy ()
Date: April 30, 2022 10:30PM

Frank,

"I" did not pick the Wire Colors!

Those are a "direct quote" from the 8th edition of Bob Helts book!

Bob did not put a Color Chart in his book, but if I remember right here are the Color wires used in the EM's:

P = PINK
V = VIOLET
BRN = BROWN
DBL = DARK BLUE
DG = DARK GREEN
B = BLACK
B/OR = BLACK with ORANGE STRIPE
GY = GRAY
B/W = BLACK with WHITE STRIPE
R = RED
OR = ORANGE
LBL = LIGHT BLUE
T = TAN

N = ???
BR = ?? (maybe BROWN?)

It has been a year of two since I have worked on any EM, and with it messed up this bad "I" would make a new Harness! People not familiar with electrical work should buy a replacement Harness from Clark's or other Corvair Vendor.

Just my thoughts!

Dale cool smiley

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Early Model Engine-to-Main wiring harness question
Posted by: Frank DuVal ()
Date: May 01, 2022 09:14PM

Ah Ha! P = Pink. I forgot.....winking smiley

Frank DuVal

Fredericksburg, VA

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Re: Early Model Engine-to-Main wiring harness question
Posted by: OldWrenchTurner ()
Date: May 03, 2022 06:16PM

As a follow through, thought I'd show everyone the finished result. Thanks again for all the advice!

You can see the before pictures above, below are the after pictures. I used part C5239 (plug) from Clark's which matched perfectly with the new engine harness (also from Clark's). Eight connectors, a bit of crimping and soldering, and voila! The original harness is back in service good as new. This saved me a considerable amount of money too (roughly $8 in parts vs. $150 for a new main harness). thumbs up




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