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I recently bought a 1977 corvette serial number 08630, and it has a new dash harness in it. The interior harness is not getting power from the battery because the firewall connection pin on the engine harness side does not interface with anything on the inside. My car also has the old-style gauge cluster without the circuit board and speedo/tach. The harness has the connection for the new style gauges with the pcb. I was wondering if the gauges changed from the old style to the circuit board style mid-year like many other things with the 77s did, if not, then what harness should I need?
By the VIN given your 77 is a early build or first design.
On the early builds there were 2 different main dash harnesses that would have been installed, one for a Manual Transmission or one for Automatic Transmission.
Either of the Main Dash Harnesses would have had the connector for the Center Cluster Gauges PCB board.
Your early build has what they called a TAP connector and there is a couple different configurations of of that...
With A/C
Without A/C
The TAP connector is located down below the Master Cylinder area photo below, this TAP Connector is configured for a A/C car with the Hood Light.
Here is a drawing I made that includes the TAP connector and the single Starter Solenoid #10 RED wire (fusible link "A").
This drawing also includes the Forward Lamp Harness to bulkhead connector (fusible link "B")
NON A/C left A/C right
Last edited by bmotojoe; Aug 22, 2022 at 02:16 PM.
And here is the early charge circuit.
Notice Figure A on the right page, that is the TAP connector
And "FROM STARTER SOLENOID" that is a single #10 RED wire that is protected by fusible link "A"
I will also provide another photo showing bulkhead connector circuits and the differences between the early and late harnesses.
Is it possible you have a Late new Main Dash Harness?
It's possible I have a late harness in the car, as it was changed before I bought it, I have come to the realization that the gauges have also been replaced by the early c3 gauges, and do not hook up to this harness. It would also explain why I am not getting power to any interior components, as the pins seem to be in all different placeson the later fuseboxes.
I just checked the pins and have confirmed that o have the late harness in my car, so I will be getting in touch with the previous owner to get ahold of the original harness. I have one question, are the center console gauges from the 79 year compatible with 77?
I just checked the pins and have confirmed that o have the late harness in my car, so I will be getting in touch with the previous owner to get ahold of the original harness. I have one question, are the center console gauges from the 79 year compatible with 77?
The center gauge clusters were virtually the same from 77-80 other than the gauge needle colors.
"I think" starting in 1981 the clock was replaced with a oil temp gauge...
1977 wiring harness change?
