Old Alfas carry a reputation for electrical gremlins almost as stubborn as their reputation for rust — but the Spider is not the worst offender, and most faults are the familiar old-car ones: tired connections, poor earths and perished wiring rather than anything exotic.
A fair reputation, mostly
While vintage Alfas have as poor a name for electrics as for rust, the Spider doesn't suffer too badly. Treat the wiring as you would any sixty-year-old car's: expect age-related niggles, not disaster.
Check the basics
On any car you're assessing, work through everything: headlights (main and dip), sidelights, indicators, brake lights, horn, wipers and the starter. A fault list that's all small stuff — a dead bulb, a lazy indicator — is normal; whole dead circuits point to bigger wiring or earth problems.
Earths are the usual culprit
As with most classics, a great many "electrical faults" are really poor earths — corroded earth straps and connection points that starve a circuit. Before chasing anything complicated, check and clean the earths; it cures more gremlins than any other single job.
Wiring and connections
Look for perished insulation, brittle connectors, and amateur additions — spliced-in wiring, extra fuses, non-original accessories — that bring their own faults. A tidy, original-looking loom is reassuring; a bird's-nest of add-ons is a warning.
What it means
Electrical work on these cars is rarely a deal-breaker — a patient auto-electrician can put most of it right — but a car with wholesale wiring problems is a time sink. Judge whether you're looking at a few tired connections or a loom that's had a hard life.