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The headlights on my Custom 8 will sometimes turn off spontaneously. I've brought this up on this forum previously and others have suggested I look for shorts, which I've done and I can't seem to find any evidence of that. Besides turning off spontaneously, there are times I can't get them to turn on at all and I have to cycle the switch many times to get the lights on. I noticed that in some Tech Bulletins (see 47T-36 for example) they talk about an accessory circuit breaker and a separate headlight breaker. And indeed it looks like there is some kind of breaker or relay type thingy near the headlight switch although this is not indicated on any of the circuit diagrams from the 48-49 years. The accessory breaker is shown on the 22nd Series diagrams and I see that just above the clock. I notice that this breaker is missing on the 23rd series. Tech Bulletin 47T-36 says the headlight switch should go through the accessory breaker and not the switch breaker and it looks like that's how it is on my car as I do see a wire that goes to the accessory breaker and comes from the general direction of the headlight switch but I can't be certain. Anyway, does anybody have any insight into this? Thanks.

Ron

There is a breaker mounted to the headlight switch. It protects headlight, parking, instrument and tail lights. A short in any of those circuits would affect that breaker only. The Aux breaker is mostly interior and courtesy lights etc and should not be in consideration. Depending on your car being a 22nd or 23rd series 49, there are some minor differences in wiring. If you don't have one a 22nd or 23rd series wiring diagrams can be downloaded from the site and might provide a better idea of the wiring.packardinfo.com/xoops/html/modules/article/view.category.php?50 Chances are that any issues on the tech bulletins have been long corrected.

As they age the breakers can weaken and carry less current than rated. Typical symptom is much like a short with the same on and off action but happening at a slower rate than if there was a direct short. If there are no shorts to be found and wiring and bulbs are stock a weak breaker is a possibility. Another possibility is the switch has become dirty and the poor connection inside is pulling a lot of current causing the breaker to trip. Even if a dirty switch is not causing breaker problems a cleaning might brighten the headlights slightly.

You can remove the switch, replace the breaker with a 30 amp stud mount breaker from Napa and also clean the switch. If replaced, make sure the new breaker is type I self resetting.

Here are photos taken by poster Jeff several years ago showing a disassembled dirty switch and another after it was cleaned. The third photo shows the headlight breaker attached to the switch.

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