Are the headlights fused?

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Lee Craner
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Joined: Sat May 04, 2019 11:42 pm
Location: Las Vegas, NV

Are the headlights fused?

Post by Lee Craner » Wed Oct 09, 2019 1:35 am

Took my 65 out for a spin last Saturday. Near the end of the ride, the headlights flashed off then back on a few seconds later. Happened two more times, then no problems.

Something, of course is wrong (one of my mantras, "things don't fix themselves"), so I drew up a circuit diagram of the headlight circuit. Seems to me that there ain't know fuse or circuit breaker in the circuit. From what I can dissect, current flows from the starter solenoid, through the master disconnect, through the amp meter, the headlight switch, dimmer switch, back through the master disconnect to the low beam headlights. I can't imagine that there is no over current protection in the circuit (fuse or circuit breaker).

What am I missing?
Lee

georgemii
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Re: Are the headlights fused?

Post by georgemii » Wed Oct 09, 2019 9:22 am

Circuit is protected by thermal breaker which is internal of headlight switch.
Actually, there are 2 breakers (for 2 circuits) built inside that switch.
Was fairly common in the era.
As you noticed, lights will cycle as breaker heats and cools.
Is mentioned in service manual.
My recommendation: replace headlight switch.

jtschug
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Re: Are the headlights fused?

Post by jtschug » Wed Oct 09, 2019 11:02 am

Certain newer headlight bulbs draw more power than the old bulbs the circuit breakers were made to run, so especially when running with the brights on, the headlight breakers can reset. On a dark night this makes it very hard to drive.

If you want to run more powerful bulbs, you could design a new power feed for them with a relay and a larger circuit breaker. I wouldn't use a fuse because you do want something that can reset.

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RedBird64
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Re: Are the headlights fused?

Post by RedBird64 » Wed Oct 09, 2019 12:02 pm

All good advice!
If you run 60/55W bulbs you'll be fine but anything bigger, like the 100W parts will cause the CB to trip.
I've been running 60/55 Halogens for many years and while they're nothing compared to modern headlights, they're sure better than the regular type.
There are also some LED replacements out there that probably out shine them all!

Scott
1964 Coupe Wimbledon white/Rangoon Red w/black int. Owned for 42 years. It was my folks car before that (second owners). VTCI # 12013.

Terry64HT
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Re: Are the headlights fused?

Post by Terry64HT » Wed Oct 09, 2019 1:20 pm

Installing relays and getting fresh power right from the solenoid is a well-documented and simple job. No matter what bulbs you use, they will be brighter. If you do this you need to protect the new power feed, not with a fuse, but a breaker. The reason your lights go off and on is because there is a problem with the circuit and the breakers automatically reset so you have some lights. Bussman makes a ATC format breaker that will fit an inline holder or a ATC type fuse panel. Make sure you get a Type 1 (automatic reset).
I have relays for my headlights, dash lights, windows and automatic door locks, so I have a fuse panel mounted behind the windshield washer bag so it's hidden but accessible.
The photo shows the area behind the washer bag with the relays for the headlights and the fuse panel below. The larger gold thing is the relay, the others regular ATC fuses of various amperages.
Damn, now why is the picture upside down????
Terry
64HT
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Lee Craner
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Location: Las Vegas, NV

Re: Are the headlights fused?

Post by Lee Craner » Thu Oct 10, 2019 12:08 am

Thanks, all. I couldn't imagine that the circuit wasn't protected. Georgemil had the answer.

The headlight switch is new, from Birds Nest. So, before I pull it as a bad replacement, I wanted to eliminate all other possibilities. That was the reason for my diagramming the entire circuit. BTW, headlamps are original tungsten, so I shouldn't have any extra current draw that would cause the circuit breaker to trip due to over load.

Lee
Lee

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RedBird64
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Re: Are the headlights fused?

Post by RedBird64 » Thu Oct 10, 2019 11:40 am

I have had the hi/lo beam switch on the floor cause them to overload and blink like that.
Might try replacing that first - they're cheap and plentiful.

Scott
1964 Coupe Wimbledon white/Rangoon Red w/black int. Owned for 42 years. It was my folks car before that (second owners). VTCI # 12013.

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