I have a well preserved 1977 Pontiac Phoenix with a 305 and auto trans. When I bought this car it only had 48,000 miles on it and the base gauge set that included a speedo, fuel gauge and some dummy lights. I did some research and learned that the part of the cluster containing the fuel, oil, temp, and volt gauge from a late 70's LeMans would fit my cluster and I managed to retrofit a tach with a clock integrated into it from a 77 trans am into my instrument cluster as well. It all looks great, like it came from the factory that way, the problem is trying to figure out the wiring.
I've swapped out the oil and coolant sensors, and figured out the wiring for the tach. My question is, can someone find a schematic for a Phoenix with gauges? Is this orange wire labeled #1 on the connector a constant hot to run the clock? Can I draw switched power for my tach from the volt gauge?
The orange wire should be a constant battery voltage and you can probably take the Key on voltage from the volt meter from the side the voltage goes into the volt meter.
You can use a test light and check for switched on voltage at the ignition switch and splice into the wire from there.
I'm having trouble locating a schematic that old but I have a friend that has old repair manuals and I will recheck the wiring from those old books.
I will follow up on this post when I find out.