I have two questions. First the radiator fan will not stop running?
Second
Both headlights work on highbeam but only one when they are not on high beam. I have replaced the lamp and same problem persists
oh…a 70’s Alfa with an electrical problem…that’s a new one.
Sorry for the levity but I’ve owned several Alfa’s and they all had quirky electrics.
Your problem will be a bad inline connector, a test lamp or meter will help you trace the problem but if you have neither of these trace the wiring back from the headlamps (it’s only a headlight when it’s on) and pull apart any inline connectors, a squirt of electrical contact cleaner and a spot of dielectric grease will fix the problem.
While you’re in the mood, disconnect the battery and give your fusebox a clean, they are legendary for playing up.
I very much doubt it’s a switch or relay problem since the switch work is common, were the problem to lie there, neither headlamp would work.
Do you mean the fan runs all the time the engine is running? Or do you mean it is electrically driven and runs with the engine off until it drains the battery ? If it is electrical, replace the relay or swap it with one with the same numbers on it if you can find one and see if that takes care of it. If it is belt driven it is supposed to run all the time.