Anybody out there know what could cause the headlamps on my 1952 Oldsmobile Super 88 to stay on high beams? When I tap the dimmer switch, the headlamps do not change, and the red bright light indicator on the cluster stays illuminated. I replaced the switch, same result. Is this system smart enough to default to brights if both low beams burn out?

 

No the system has no distinct failure mode. I don't know the color codes for your car, there is one feed wire from the headlight switch to the floor switch connector. There is a single wire to the low beams and 2 for the high beams, 1 goes to the headlights and 1 goes to the red light in the dash. Unplug the switch, turn the lights on and see if you have any headlights. The jumper the wire that has power to the single wire, the low beams should light, then jumper to the terminal with with 2 wires and the high beams should light.

Your new switch may be defective.

 

Defective floor switch. Replace it before the high resistance in the switch does a melt down of your head light system wiring. This switch is a common problem, since it is exposed to moisture from your shoes after getting into the car during a rain storm. Sometimes you can salvage it by soaking it with PB Blaster, but even NOS units are reasonably priced. Just don't buy a modern Made in China, because they are junk, right out of the box.

 

I read the OP to state the switch has already been replaced. I presume the switch replaced is the dimmer switch on the floor.

Of course, it would not be impossible/out of the ordinary in this day and age for new floor switch to be defective?

 

Rather that replacing parts that don't need to be replaced, how about a little troublshooting first...

The headlight circuit is VERY simple. There is a wire from the headlight switch to the dimmer switch that provides power when the headlight switch is on. The dimmer switch then has two output wires, one for the low beam circuit and one for the high beam circuit. Unplug the dimmer switch and use a VOM to test continuity from the input wire to each of the output wires with the switch in both low beam and high beam positions. This will immediately tell you if the problem is in the switch. If not, then you have a short between the high beam and low beam wires out of the switch.

 

I don't know if cars that old had much in the way of fuses, but maybe while you're fixing the problem installing fuses for the headlamps might be a good idea.
If it doesn't have any that is. Very few British cars of that age had any protection for their headlamps.
British Fords had one fuse - for the turn signals.
The best fuse systems in European cars of that era were in FIATS believe it or not.

Roger.

 

Olds didn't use a fuse in the headlight circuit. There is a self-resetting circuit breaker built into the headlight switch.