Electrical issue, any ideas?

[Barry Wolk]

I took a closer look at your photo and it appears that your front window switches don't appear to be self-centering, which can activate a relay coil, but have no power to move the window. There's a control circuit and a power circuit in each switch. That would account for a battery drain and a sound, but it may not be the circuit breaker you're hearing.

This is a new one on me.

One last thought. Check where the black wires come from on that plate. Only the wire from the harness should go to the grounded side of the circuit breakers. The other stud is for ground wires from motors, lights and lighters. Mounting any of them on the wrong stud leaves the circuit protection defeated. The black wires can easily be confused. Doing it wrong can easily cause a fire. Normally you think of circuit breakers that open the hot wire, but on a car switching is how the circuit accesses a ground.

[Pat Marshall]

I took the lower driver's door panel off and it turns out everything in the door was OK, and it seems the sound was coming the other way through the drivers kick panel ducting into into the air duct at the bottom of the door and up into the door. It was very illusive. I was thinking the sound was coming from a relay, but since there are no relays under the dash, that wasn't it.

The sound was omnipresent - it could be heard in the driver's door, in the engine compartment (like it was coming from the brake booster area) in the driver's footwell where it seemed the sound was coming from everywhere.

The only thing left was looking for the problem below the dashboard!

We got lucky! After I put the lower door panel back on, I took the underdash plate between the steering column and the driver's kick panel off. There was no arcing or other evidence of problems, except that darned sound, which was really loud after the plate was removed. Next my long-armed son, Dave, reached under and started feeling around, and when he touched the light switch he felt that it was vibrating heavily in concert with all the dimming and flickering of the car lights.

Dave disconnected the light switch - the symptoms went away! I immediately ordered a new switch from Dennis Carpenter.

The switch will be here in a couple days, so we'll find out if it actually was the switch, or the switch was reacting to an issue elsewhere. However, I now remember just before the problem started I was having trouble getting the switch to properly control the light level in the dash pod dials.

In the meantime, we taped off the electrical wires and stuck the old switch back in. It looks like it never happened, and I'll be off to a car show tomorrow. I just can't drive at night for a few days.

I'll give a report in a few days!

Thanks for everyone's responses!

[tluke]

So I've had this type of issue twice, on separate cars, both '55 Cadillacs so this may not apply but in both cases it was the thermal breaker in the headlight switch that kept tripping due to shorts in wiring elsewhere. I've never had the headlight switch out on my Mark II but if there is a thermal breaker that could be the cause of the sound, but not the cause of the issue. In one case there was an intermittent short in the wiring to the headlights that was grounding out and tripping the switch's thermal breaker, flashing the headlights and clicking. The breaker would cool down once tripped and reconnect briefly then the short would trip it again. Each time there was a click made by the breaker opening and closing (vibrating). On the other car it was a short in a wire to the rear clock (limo). On that car the body wiring for interior lights/clocks etc. came straight off the headlight switch so every time the clock rewound it would trip the thermal breaker in the headlight switch and if the headlights were on, they'd go out then come back on in a few seconds. That was tougher to resolve. Before finding it I cleaned the contacts on the breaker which was a good idea anytime the switch is out. Later model Cads that year put in a fuse in the body wiring circuit that would blow first and prevent tripping the headlight switch for anything but a short to the headlights themselves. Hopefully it was just a short in the headlight switch itself, maybe the rheostat shorted out causing the issue with dimming the instrument lights mentioned.