The rather complex looking wiring section shows the voltmeter wired in via the green positive wire & the black earth wire. This section then plugs into the connector under the dash as per the left photo.
Wiring in the lights then proved another challenge as three gauges had the red wires but only one, the voltmeter had a negative. Also, the Capri lights can be turned on without the ignition so again finding the best place was interesting. The earthing of the lights & the voltmeter could go to the same good earth point. This is how the panel looked when attached with all the wires exposed.
Now to add another variable was the tachometer. The first problem was were to place it. The obvious place was some where to the right of the dash pod but there are no real places to firmly attach it without drilling holes. I then tried some double sided tape but the gauge fell off after about 20 minutes. Next was some stronger Velcro tape. That seemed much more promising so I then went ahead with the wiring. The tachometer has 4 wires: red for power, green to the negative side of the coil, black for an earth & white for lights. I joined the power in wire to the same junction as for the voltmeter & radio, the green went through the firewall to the coil, the earth was also joined with the same wires from the other gauges & bolted to the dash frame, the light wire went with the other lights to a junction under the dash that linked to the car lights which are quite independent of the ignition. Here are some pics.
Unfortunately, the Velcro tape wasn't strong enough & the tachometer fell on the floor after a short road test. For the moment I have just attached it on the RHS parcel tray area until I find a better solution. I have also tried to make the other gauges look a bit better with some tape and a thin board insert underneath. A bit more to do until I am really finished.
With the first turn of the ignition, I was quite apprehensive & was hoping that no sparks & smoke would appear but after double checking all the wiring, the car started & all the gauges were operating as one would expect.
Was it all worth it? Maybe, so we shall see.