Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

[Norris W.]

This car had the most butchered under hood harnesses I've ever seen, so I replaced everything under there with new harnesses. It's a '66 L79 NO TI. On the engine harness that goes across the cowl, there is a double pink wire that comes out of the harness. It obviously goes to the coil. Further back toward the master cyl there is a single pink wire, which I would assume goes a the ballast resistor, although the laminated wiring schematic I have isn't real clear. So if the single pink goes to one side of a ballast resistor, what goes to the other side of the resistor? All wires at the starter motor, including the ground are connected properly and I don't seem to have anything else under the hood to go to the resistor.

So right now I'm at dual pink under + side of coil and distributor wire should be at - side of coil, but I have no fire and neither of the pinks are hot with the ignition on.

[Russ S.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Should be a single pink at both ends of the resistor.

[Norris W.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

I'm still not following. Double pink goes straight from harness to + side of coil. That shows clearly on the schematic. A single pink shows on the schematic as going through a resistor and continuing on as one of the doubles at the coil. I haven't ******ed the dash out to see where this other pink comes from and if it has some type of resistor in the middle of the wire (that's how it looks on the diagram) but it leaves me with a single pink out of the harness with a connector on the end as if it would go to a ballast resistor. So, the question is, if it gets this pink into the resistor and another pink out, where does that pink out of the ballast resistor go? The schematic doesn't show the + side of the coil as having 3 pinks under it.

[Kenneth F.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

On my 1966 L-79, a single pink wire coming out of a larger loom rear of the master cylinder goes to the ballast resistor. Another single pink wire comes through a large grommet in the firewall just rear of the ballast resistor, goes to the second side of the B/R. Two pink wires attached to a single wire end, goes to the positive side of the coil.

Ken

[Bill C.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

On my 1966 L-79, a single pink wire coming out of a larger loom rear of the master cylinder goes to the ballast resistor. Another single pink wire comes through a large grommet in the firewall just rear of the ballast resistor, goes to the second side of the B/R. Two pink wires attached to a single wire end, goes to the positive side of the coil.

Ken

X 2

I believe the harness that passes through the grommet sends wires out for the ballast and the wiper motor...

Bill

[Richard M.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Yes, coming out of the big grommet to the right of the wiper motor(as viewed from front), is a bundle of wires from the Main Dash Harness for the wiper/washer, backup lights connector(iirc on '66 even if not optioned) and a single "thick" gauge Pink wire with a u-shaped terminal on its end.

On TI cars a female plastic housing enclosing a male blade terminal which mates to the TI Harness male plastic housing enclosing a female receptacle terminal

This thick Pink wire is sourced from the Ignition switch when in the RUN position. This is to be installed at the lower screw of the firewall mounted Ballast Resistor. The other end(top) of the Ballast is connected to the single "thick" Pink wire in your engine harness with u-shaped terminal end. As you've already done, the u-shaped spade terminal with both the thin AND thick Pink wires goes to coil+.

There is no "resistor wire" in a points ignition system anywhere. I don't have a copy of your laminated wiring schematic, but the "resistor" they're showing in the ignition Pink path is in fact likely the "Ballast" resistor, and they're not showing the separate terminal connections to it.....which they should......to clearly eschew obfuscation(*).

Rich
(*)eschew obfuscation. = avoid confusion.

[Norris W.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Thanks guys. It sounds like I'm missing a pink wire through the cowl. The previous owner had a wire though the cowl jammed under the side of a fuse on the block that is hot when the ignition is on. I guess he replaced the pink wire for whatever reason. Sounds like more time upside down in the floorboard and probably a new dash harness would be a good idea although I DO HATE replacing dash harnesses.

[Tom O.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

1966 L72
Norris, good afternoon. I'm curious if you resolved the pink wire(s) issue. I'm confident I don't have the technical skill set of most members but I took a shot at replacing a really beat up harness. All seemed to go well with Lectriclimited harness until I ran into similar confusion over the pink wires. I can't seem to locate the ignition ballast resistor to connect the single pink near the break booster. A picture or two would be very helpful if anyone out there has any.

[Richard M.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

1966 L72
Norris, good afternoon. I'm curious if you resolved the pink wire(s) issue. I'm confident I don't have the technical skill set of most members but I took a shot at replacing a really beat up harness. All seemed to go well with Lectriclimited harness until I ran into similar confusion over the pink wires. I can't seem to locate the ignition ballast resistor to connect the single pink near the break booster. A picture or two would be very helpful if anyone out there has any.

Tom,

The L72 required Transistorized Ignition(TI), RPO K66. If your car still has that, then you won't have the Points Style ignition Ballast resistor.

Does your distributor have 2 wires coming out the bottom, terminating to a 2 terminal plug in the harness? Also check for the TI Module(box) located in the Driver side front grille area directly ahead of the front wheel. It's held there with three 1/4-20 bolts and you'll see the 3 nuts in the wheel well side.

The TI system would have a special connector at the big Pink wire coming out of the firewall grommet. This would connect to a White wire which would be part of the separate TI harness. All Main dash harnesses have the U-shaped terminal which would normally connect to the Ballast on Non-TI cars. If TI, then it gets cut off and replaced with a terminal to mate with the White wire in the TI harness I mentioned.

See this thread for more info if your TI system is still intact.

https://www.forums.ncrs.org/showthread.php?115713-TI-ignition-conversion-question&highlight=TI+harness

Rich

[Tom O.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Rich, thank you so much for the quick response!
Does your distributor have 2 wires coming out the bottom, terminating to a 2 terminal plug in the harness? YES.
Also check for the TI Module(box) located in the Driver side front grille area directly ahead of the front wheel. YES.
This would connect to a White wire which would be part of the separate TI harness. If TI, then it (?) gets cut off and replaced with a terminal to mate with the White wire in the TI harness I mentioned. A LITTLE CONFUSED HERE. Tackle it tomorrow with a fresh brain. Thanks again!

[Mel S.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

The two single pink wires go to the ballast resister and the double pink wires go to the coil. i have a 66 with air and power windows with 27,700 original miles. Starts every time.
Good Luck
Mel

[Tom O.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Good morning Rich. Can I email you some pictures I took? I imagine you would recognize what I may have be goofing up. Single test picture below to see if I can copy and paste here. Tks. T.

1966 L72 Electrical.jpg

[Richard M.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Rich, thank you so much for the quick response!
Does your distributor have 2 wires coming out the bottom, terminating to a 2 terminal plug in the harness? YES.
Also check for the TI Module(box) located in the Driver side front grille area directly ahead of the front wheel. YES.
This would connect to a White wire which would be part of the separate TI harness. If TI, then it (?) gets cut off and replaced with a terminal to mate with the White wire in the TI harness I mentioned. A LITTLE CONFUSED HERE. Tackle it tomorrow with a fresh brain. Thanks again!

Edit.... Tom I was composing when you sent those photos. Let me take a look and get back to you.....


Tom, It certainly appears that you have TI and I'll have to make the assumption it is still operational. A few photos of your TI harness near the ignition coil, coil itself, distributor, and the TI connectors near the firewall would help clarify.

The "it" I was referring to was from the previous sentence..... the U-shaped terminal.

"All Main dash harnesses have the U-shaped terminal which would normally connect to the Ballast on Non-TI cars. If TI, then it gets cut off and replaced with a terminal to mate with the White wire in the TI harness I mentioned."


The Pink wire in a new harness needs a different terminal to connect it to the TI harness white wire connector, which is a female blade terminal with male plastic housing. This White cloth covered TI only resistor wire replaces the Ballast in a points system. Don't confuse this White wire with the White wire going to the Ignition Coil + terminal.

If your TI is still functional, you should see this White wire coming from the TI harness. It must have been connected to your old Main harness Pink wire if the engine ran. You may need a new male blade terminal to replace your Pink wire U-shaped terminal. Vendors sell a kit for TI conversion. It looks like this....
e-863_71.jpg
https://www.zip-corvette.com/66-67-t...rsion-kit.html

Here's a local copy of the info photo from the thread I linked earlier. Applies to both 1966/1967. See the notes in the 3 upper right text boxes. In this photo the U-shaped terminal has already been cut off and replaced with the blade terminal and plastic housing. Hard to see it in this photo.



Also use AIM page K66 A3 but it can be quite confusing if you're unfamiliar with TI wiring. I added a few notes on my copy.




===

[Richard M.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Tom which new harness did you replace? Engine harness or TI harness or Main harness?

Rich

[Richard M.]

Re: Replaced under hood harnesses on 66 L79. Can't figure out pink wires.

Okay, It looks like you have a new Engine harness. I think?

Your bottom middle photo. This is what I was trying to describe earlier as I thought you replaced the Main harness. The Pink wire comes from the IGN switch and I see it's connected already to the White resistor wire. This also confirms to me you have a operational TI ignition system.

However, I'm a bit confused about your upper left photo. It shows the Black/Pink wire but it is already connected to a wire, the one with the Blue tape. Is that wire White or Pink? It looks Pink to me. Was this a "before" photo? If so, keep reading as I think this is your old Pink wire going to the Starter Solenoid R terminal.

Also confused about your bottom left photo. I see 2 Pink wires on Coil +. TI will not have those there. Maybe you removed them and show in the upper right photo.

The Double Pink wires in your upper right photo..... Both are tied to a single U shaped terminal. On a points ignition the terminal connects to Ignition Coil +.

One of the 2 Pink wires goes to the Starter Solenoid R terminal. The other goes to the Ballast resistor if Points Ignition, which would not be used for TI.

Cut the U shaped terminal off the double Pink wire pair and discard the terminal. Now you have 2 separate Pink wires. You will have to use a test light or ohm meter to find which is which. The one that goes to the Starter Solenoid R terminal is the one you need. You need to add the blade terminal on that wire. It then connects to the one wire connector(Black/Pink tracer), which eventually connects to the Distributor connector.
The purpose of this wire is to provide full battery voltage during crank to both the TI Amplifier Module and to the Distributor Pickup coil.

The other(unused) Pink wire can either be completely pulled and removed from the engine harness. The other end of this wire will have a U shaped terminal. If you want to keep it you can tape the ends and secure it somewhere. It is now just a loose wire doing nothing.

What I do not see in your photos is the White wire(from TI module) going to Coil +, or the Black wire(ground from TI module) going to Coil -.

Rich