My 74 1.8 quit on me yesterday. I've narrowed it down to no ignition power. The gas gauge and indicator lights don't respond to the key switch being on. The starter will turn over and the fuel pump is running. I've checked the fuses under the dash on the left side and they all seem good. I'm headed over to where it has been towed to work on it later but there is limited internet access there. I would like to gather any info I can before I head out.
Thanks for your interest.

Bad ignition switch.

I forgot to mention that the radio responds when the ignition switch is on. Does this make a difference?

Black wire on relay board plug is the ignition feed. It goes directly back to the ignition switch. Ignition switch gets power directly from one of 4 red wires at battery termainal.

Where is this relay board located?

More info to share. I didn't think these two were related but after more research it seems it could be important. The tach quit the day before.

Check the wires on the coil. There should be at least three. One big black on one side and two smaller ones on the other side, one black with a purple stripe and a green (or whatever color comes fron the condensor on the distributor).

More info, I don't have power to the first 7 fuses under the dash ever.
#8 has power to it, ignition on only
#9 no power ever
#10 and #11 have power always

FYI #8 is the only one that responds to the ignition switch.

Wiring Diagram.

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We have IGNITION!
I found an inline fuse where some PO tapped in to the power supply blown. Thank everyone for the support and information, especially Mike for the wiring diagrams.

Motor starts and runs but no tach or fuel readout.
I'm working on this now.