Question On The 66 L72 Wire Harness With K66 Option

[Larry E.]

We all know that the 66 L72 had a mandatory K66 option. We know there was a added K66 wire harness
for the TI Box upfront by radiator. We also know that no "Ballast Resistor" was used with this system.
Here is my question>Was there also a different wire harness used on the firewall to eliminate the wires
to the ballast resistor? Or was the wires Cut or Taped to the existing firewall harness similar to the technique
used with the C48 (Heater Delete Option) wires to the heater motor/controls?? Thanks in advance>Larry
P.S. The A.I.M. and Judging Manual is unclear on this.

[Richard M.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Larry, No there was no special engine harness for K66. They all had the heavy gauge pink wire which normally went to coil+ from the output end of the ballast resistor.

It is my understanding this wire was cut at the coil+ terminal end and pulled from the harness.

The small gauge wire from Solenoid R terminal, also tied to the ballast pink wire previously removed, was modified to connect to the K66 harness. A spade terminal was attached to connect via a plug to the PU coil and TI module, as outlined in the K66 AIM section.

Rich

[Larry E.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Larry, No there was no special engine harness for K66. They all had the heavy gauge pink wire which normally went to coil+ from the output end of the ballast resistor.

It is my understanding this wire was cut at the coil+ terminal end and pulled from the harness.

The small gauge wire from Solenoid R terminal, also tied to the ballast pink wire previously removed, was modified to connect to the K66 harness. A spade terminal was attached to connect via a plug to the PU coil and TI module, as outlined in the K66 AIM section.

Rich

Rich: Thanks for the comments. I do not doubt that they did what you indicated but is seems strange to me this is
not explained in the A.I.M. as they do with the C48 option in detail. Was there some type of "Assembly Instruction
Paperwork" given to the people that did this task? Larry

[Richard M.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Rich: Thanks for the comments. I do not doubt that they did what you indicated but is seems strange to me this is
not explained in the A.I.M. as they do with the C48 option in detail. Was there some type of "Assembly Instruction
Paperwork" given to the people that did this task? Larry

Larry, There may have been some instruction as to what to do with that Pink wire, I am unsure.

My gut tells me they pulled the wire as it would be easier than trying to conceal the cut ends, possibly leaving bare wire exposed to view.

It is also very possible that these wiring changes were made "on the bench" for cars allocated to get K66. It wasn't a unique part # but I can't imagine the guys on the assembly line cutting wires and splicing terminals in several places. I'd guess it was done before assembly into the car.

Rich

[Mark L.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Take a look at the 66 AIM and see the K66 option. It describes what the line workers needed to do.

[Larry E.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Take a look at the 66 AIM and see the K66 option. It describes what the line workers needed to do.

Mark: Unless I reading it wrong or missing a page in the A.I.M. it still does not say how the two
wires going to the ballast resistor (In a Non-K66) car where eliminated. I'm thinking that Richards
explanation may be the answer. >"It is also very possible that these wiring changes were made "on the bench" for cars allocated to get K66." but who really knows? Larry

[Alan D.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Larry, you maybe assuming that the wiring to the ballast resistor and ballast resistor was already installed before the TI was added, YES?
Do not think ( ) that was done. Believe the options were known before car was assembled, therefor the Ballast stuff was never installed.
Just looked at the MIDYEAR CORVETTE ASSEMBLY PROCESS, 2011 NCRS National Convention Technical Seminar,
Presented by John Hinckley, Michigan Chapter
and on page 8 he lists the following "Ignition ballast resistor or T.I. harness and amplifier"

That leads me to believe my assumption maybe correct.

[Larry E.]

Re: Question On The 66 L72 Wire Harness With K66 Option

[QUOTE=Alan Drake (43261);905474]Larry, you maybe assuming that the wiring to the ballast resistor and ballast resistor was already installed before the TI was added, YES?

Alan>No on the Ballast Resistor; maybe on the wiring. It(wiring) was installed with the C48 option with that option known was it not? This goes back to my original
question if a different firewall harness was used with the K66 option. Larry

[Mark L.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Mark: Unless I reading it wrong or missing a page in the A.I.M. it still does not say how the two
wires going to the ballast resistor (In a Non-K66) car where eliminated. I'm thinking that Richards
explanation may be the answer. >"It is also very possible that these wiring changes were made "on the bench" for cars allocated to get K66." but who really knows? Larry

Larry, there is no doubt it can be confusing especially with what seems like limited info in the AIM. After looking at my car I believe what happened on the ass'y line was the pink wire that came through the firewall was removed from the resistor and a connector was installed. The TI harness has two white resistor wires coming out of it. One was then connected to the pink wire and the other was connected to the coil. Another pink wire that comes out of the harness that runs across the firewall had a connector installed and this was the black lead to the coil.
My memory (such as it is) tells me there is a more detailed wiring diagram that was provided with the TI harness purchase. I'll see it I can find it.

[Alan D.]

Re: Question On The 66 L72 Wire Harness With K66 Option

I have an original 1964 harness for my TI option car, if it will help can take a picture of the area?

[Richard M.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Alan, Yes, and can you show if the 12G (Blk/Pink) wire is totally missing, or cut and left in the harness? Two ends if it is. but...

... Keep in mind the Ignition coil is wired differently between the 64-65 K66 and the 66-71 K66. This necessitated 2 different TI Harnesses.

But the 12G Pink wire, from the ballast output if non-K66, in question, is common to both(early/later) K66 optioned engine harnesses. The question asked was if there were 2 different Engine harnesses applicable, on the same model year car.

There was only one part number engine harness for K66 or non-K66, but 2 terminals were different and that infamous 12G Pink ballast wire wasn't used for K66. Where the terminals were changed is really a uncertainty in my mind. But as mentioned I suspect these changes to the engine harness were made before it was installed in the car. With the line moving fast I just can't see a worker fiddling with terminals and crimpers and plastic terminal housings.

Regardless, where it happened is somewhat of a moot point when it comes to how to interpret the AIM and it's inaccuracies with regard to TI. So this afternoon I took a copy of the AIM and colorized it with some notes. In the exercise I discovered some errors. Firstly the color code is wrong for the wires to modify. They state Black with Pink stripe, but that's for 64-65. The 66-67 uses solid Pink. Secondly, they have lines pointing to the wires to modify incorrectly shown. Another error. No wonder it's hard to interpret.

This is the 1966 AIM UPC K66 Sheet A3 with the errors. Compare to the enhanced page I made below.
K66_AIM_1966Orig.jpg

This is the 1966 AIM UPC K66 Sheet A3 with my notes and some enhancements.
K66_AIM_1966.jpg

This is a 67 K66 engine bay with some notes also.
TI_1_mod.jpg

[Larry E.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Richard>Wow; what a complicated mess this was. How would you like to be a new guy on the line put here after the
regular guy called in sick? Larry

[Richard M.]

Re: Question On The 66 L72 Wire Harness With K66 Option

Richard>Wow; what a complicated mess this was. How would you like to be a new guy on the line put here after the
regular guy called in sick? Larry

Haha Larry. I was that guy when I did my first TI Harness mods to a 67 I restored many years ago.

Rich

[Richard M.]

Re: Question On The 66 L72 Wire Harness With K66 Option

I can't seem to get this out of my head. This morning I remembered I had several engine harness lying around. I found a 1966 non-TI engine harness and a 1967 factory equipped TI engine harness. I opened them up for research.

This helps support the missing Pink "ballast to coil+" wire from the factory on K66 equipped cars.

Here is the 1966 harness. Note the "ballast" pink wire goes into the harness and tied at the u-shaped terminal with the Solenoid R wire for Coil+. Note that it does not appear to be a 12G wire as 1967 wiring diagrams show and are so equipped. This was likely a change in 1967, along with the addition of fusible links, etc.
66_Open1.jpg

Here is a 1967 original engine harness from a documented L71 427/435hp car. Note the Pink wire is not there. It was removed "somewhere" at the factory, on the bench, or on the line.
67_TI_Open1.jpg

If you are replacing the engine harness on a K66 TI car, it is recommended to remove the Pink "ballast" wire from the harness.

Rich