Pluggable C2 Corvette Dash Cluster Harness
This information was written for a 1965 Vette but should apply to all 1963-1967 Vettes. Main differences will be wire color and you will need to substitute correct wire colors.
I used the word "MODIFICATIONS" but also could have used "UPGRADE" or "ADDITIONS" so substitute whatever one that seem to work best for you. Other may use "DESTROY" or "RUIN" J
NOTE: Not for the faint of heart (NCRS types) JJ
"If it ain't broke don't fix it" comes to mind with this project JJ or "If I modify it for easy repair it will never break" BUT when I installed a new wiring harness a few years back I thought that would be the LAST-TIME-EVER to work under the dash (67 years old with major back surgery in 1982). Well this is my second time to pull out the cluster and I figure if I make it easier for the future I won't have to.
And those of you that have had below pic staring at you and anticipating putting all the GRAY WIRE BULBS back in know what I'm talking about AND not putting the Flashing Brake & Lights in reversed.
I had seen where others had suggested extending ALL the wires that plug into the cluster and that sounded like a viable solution so I started to formulate a plan and that's when I realized I would still had a bunch of wires hanging around that needed to be plugged in to correct holes. That's when I decided that using multi-plug connectors would do the trick.
So I started with two connectors like below and started planning from there.
After reviewing wiring diagram and ripping an old harness apart and after many many variations I came up with the following:
Few of things to note here: There is a 12v switched wire running through the connecter which is for the VOLT METER and LOW VOLTAGE (Idiot) WARNING LIGHT that I added, well actually it is the brown wire that normally had a capacitor on the end. Also note one plug labeled "GRAY LIGHTS" which refers to the GRAY WIRED LIGHTS (11 in total -- 9 + ignition switch + lighter) that plug into the cluster. In the original harness ALL the GRAY WIRES are bussed together (see below). Just for clarification there is also 3 more GRAY WIRES in the harness 2 for clock and 1 for radio that are not touched and remain stock.
What I did was cut off (ouch) all (11) gray wires and capped off 10 of them and used 1 that feeds into the connector then I bussed the gray wires back out on the back of the cluster. Connections were either soldered or crimped but in all cases they were pulled on HARD to insured they would stay together.
And I did not touch Ignition Switch, Wiper Switch or Light Switch wiring as they are at the bottom of the cluster and they are big and easy to plug in. Lighter wire change to add fuse which I will talk about later.
Building & Testing
Dash Harness Side of Connectors
Testing was simple - just used extra 12v battery I had laying around and hooked Ground wire to connector then 1-by-1 test light connectors. To test all Gray Wire light just took one (1) wire at connector J Volt Meter and Idiot light were both test with one (1) wire. Flashing Brake & Lights (257's) each took two (2) wires. The Fuel & Temp gauge took a little more to test and those test was just to insure the connection worked as nothing else down stream was changed. Here how I tested them ==> Fuel/Temp Test
I needed two (2) items fussed, 12v Switched & Lighter, which were fussed before but you had to stand on your head to get to them so while I was wiring I extended the wires to each and placed fuses in a small plastic box and is mounted out of sight on the driver side behind radio access panel.
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