headlights always on high beams

I just got the car and of course there are some electrical issues. dead fuel gauge , lights on high beam , no horn through the steering wheel. It doesnt look like the wiring was messed with a whole lot except when someone put a cassette player in years ago. I have some things to try. Ive already got a lot of info on this forum. Im just trying to be super careful with 45 year old wiring not to rip and tear . Thanks.
Did you check all the ground wires to the headlights? A bad ground will cause this. Seen it before.