Why does my Alfa Romeo Spider keep killing batteries or have electrical gremlins?

Short answer: On a Spider that kills batteries, do a drain test first: with everything off, find what's still pulling power, starting with the radio and the fan. A fan that runs with the engine off is often the relay. One dead headlight on low beam usually means a corroded inline connector. Clean the fuse box; owners say it causes a lot of gremlins.

Symptom: The battery goes flat after sitting, the battery light stays on, the radiator fan won't shut off, or a light works only some of the time.

What to check first

1. Make sure the radio and lights really go off with the key out.
2. Do a parasitic draw test with a meter between the battery post and cable, pulling fuses one at a time.
3. Swap the radiator fan relay if the fan runs with the engine off.
4. Unplug, clean and grease the inline connectors on the headlight circuit.
5. Clean the fuse box contacts with the battery disconnected.

Likely causes

1. Parasitic draw. Something is drawing power with the key off, like a radio that stays on, a stuck relay or a short to ground.
2. Stuck radiator fan relay. If the electric fan keeps running with the engine off, the relay is a common suspect, and it will flatten the battery.
3. Corroded inline connectors. Older Alfas have plug connectors in the harness that corrode. One bad connector can kill one headlight on low beam.
4. Dirty fuse box. The fuse box on these cars is known for poor contact. Cleaning it fixes many intermittent faults.

What it usually costs

Owners in these threads didn't post prices.

Is it safe to keep driving?

Mostly yes, but a dead headlight at night and a battery that dies on the road are real risks. A short to ground can also overheat wiring.

DIY or shop?

Nearly all of this is DIY with a cheap multimeter.

Recalls, bulletins and complaints in plain words

• Related recalls: NHTSA lists 83V005000 (some 1980-1982 Spiders: the ignition switch is defective and can cause starting trouble) and 92V076000 (some 1991-1992 cars: the glove box map light can develop a short circuit). Either could look like an electrical gremlin. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. A count is not proof of a defect.
• NHTSA complaints: 0 keyword-matched complaints for Alfa Romeo Spider 1979–1994 (of 4 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-30; keywords: battery, electrical, light, fan, alternator) (NHTSA returned no data for 16 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 1986 Alfa Romeo Spider Draining Battery on Car Talk, a 1986 Spider owner had killed several batteries, the battery light stayed on, and the radio stayed on with the engine off. A specialist said the alternator was fine. Members said to do a proper battery drain test, or take it to a good independent shop that knows electrics.
• In Troublesome lights and fan 79' Alfa Romeo Spider on Car Talk, a '79 Spider had a radiator fan that wouldn't stop and one headlight that only worked on high beam. Members said to swap the fan relay and to trace the headlight wiring for a bad inline connector, clean it and add dielectric grease, and clean the fuse box while at it.

Quick tip

With these Italian cars, clean every ground and connector before you buy parts. It's usually the connections.

Vehicle focus: Alfa Romeo Spider, 1979-1994.

Safety / mechanic note

Short circuits can overheat wiring. Verify with a mechanic.