Packard Forum Index » Post-War (1946-54)

While driving my Custom 8 in the early morning dark the headlights suddenly went off. I cycled the button and still no lights. Then, just as suddenly they came back on again. Anybody encounter this phenomenon or have any idea what's going on?

The circuit breaker is tripping. It self resets after a few seconds and will keep cutting off and back on until the problem is resolved or the breaker fails. Could be a short in the wiring or a bad dimmer switch or it could be the circuit breaker has aged and no longer can carry it's full rating.

The circuit breaker protects a great deal of wiring from 48 on -- tail, head and parking lights and dash lights. 47 and earlier it is mostly head and park. After the breaker, tail and dash on 47 and earlier models should feed thru a secondary fuse which would blow and stop the breaker from tripping if the problem is in that part of the circuit and if it has factory wiring.

Don't remember which car you have but the breaker is attached to the rear of the headlight switch and replaceable from 48-56 but built into the switch and not separately replaceable from 35-47.

Interesting. Well, I guess I'm not that surprised. It's a '49 Custom 8 and when I purchased it the left from blinker kept blowing fuses and I had to rig up a separate wire to get it to work since I couldn't isolate the short. I guess I'll have to take a good look at the wiring again and see if there's something obvious ( stripped insulation or something). I'll check that breaker too. Thanks a bunch for the info.

If it still has the original harness that old rubber and fabric covered wire is famous for the rubber drying and cracking. Flexing can cause a chunk to break off which is obvious if the wire is exposed. Unfortunately it can even happen and be hidden under the woven outer braid. If the harness is moved and bent hard enough, with no where to go the rubber can break into tiny pieces inside the loom and short to an adjacent wire if that wire is also damaged,

If it only happens when the headlights are on you can rule out parking light wires since those are not on with headlights. The trunk around the tail lights and sockets is a good place to look and another place is on instrument light sockets. The old insulation in addition to drying and flaking off can shrink back at the ends. If there is enough vibration it could allow the conductor to short where the wire enters the center hole in the socket shell.