You’ll remember I mentioned in the original post that this is where the old tach’s backlight feed was tapped, and I used it to feed power to the new tach, which may have been a mistake.
Fuel, temp and oil gauges are working at the moment, but the fuel needle is still tending to ‘wander’. Tach is the same (visibly getting power, now from the fuse box, but not responding to the tach signal).
Maybe Redfish has an idea about the wandering fuel gage.
I know its a PIA, but if you wanted to rig a 22 ohm resistor to the fuel sender connector, connect the other end of the resistor to the ground strap (fuel line), the gage should read about 1/2 steady when the car is running.