Tom: To add to Ron's suggestions, I'd clean and inspect the fuse block, ensuring there's no corrosion on the fuses or that the spring contacts have not weakened. I bend the bottom contact on the fuse block upwards, so that when you insert the fuse, it stays tight and lessens the buildup of corrosion. Damp weather has been known to cause electrical faults, especially if there's a coating of engine oil and grime that can act as an elelectrical conductor.

Lastly, on my 1960 Amazon, there's a black plastic connector, on the inside fender wall near the radiator on the driver's side that likewise can become corroded, not allowing the contacts to mate. It's worth a look. The movement of the car, can sometimes cause random faults and I've found the grounding straps to be somewhat inadequate, at least on the early Amazons.
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Cam a.k.a. CVOLVO.COM