Hey guys have a question about something that has been happening but I haven't really gotten into yet. My headlights.... I have a 12v system all updated wiring with a new fuse box harness and switches. But for some stupid reason my headlights and taillights go out on me. I've searched before I posted and I found similar posts but nothing that concrete matched what I have going on. I'll be driving and then out of no where's lights cut out. Dash lights included. But give it 5-10 seconds and they're back on. Now once it starts happening it happens I'm quicker intervals. Doesn't take as long for them to cut out. I've replaced the switch already. I have a standard pull switch. Half is running lights. All the way out is headlights. Now my turn signals will still work during this time. Which is why I thought the switch. But I've replaced it. Fuses are good. Don't appear to be blown in any way. I mean the lights work. They just cut out intermittently. The only thing I can think of is something is getting hot and shutting down and then cooling enough to let them fire again but not for long because they're hot. A short I don't see them coming back on again. I guess I could leave em on and sit with the car not running but Im not sure they'll get hot enough just sitting on. I was wondering if any of you have experienced this.
the bi-metallic circuit breaker on the headlight switch is probably overheating and cutting off the lights. too much amperage through that circuit. maybe put a relay in the headlight circuit.
You must have a breaker in the fuse block instead of a regular fuse. They are heat activated (short) and reset. Also a ground somewhere in the light system. Most new fuse blocks use them. The Wizzard
circuit breaker kicking on headlamp switch ,sometimes this can be caused by wiring not heavy enough for halogen sealed beams if that is what you have ,you can fix it by wiring in standard relays available pretty much everywhere direct to main power source (battery ,or starter solenoid etc) usually you have a hot wire to relay ,use the present low beam wire as a tripper for relay, a ground is one terminal, and other terminal from relay to headlamp, repeat this for both high and low beam so you will need two relays if this is the problem, another thing you could check is make sure the dimmer switch is good and no corrosion anywhere this build resistance can cause breaker too trip, hope this helps take care
Sounds like you are ether loosing a ground or you have a bad switch. I had a headlight switch with a fuse attached and I was having the same problem,,running down the road in the dark and bang no lights. My problem was the phenolic cap on the switch had deteriorated and cracked,,for some reason it kept blowing the fuse,,replacement and my problem was solved...BTW,,it took me almost a year to finally track the culprit down.HRP
What light switch are you using? Many have a breaker built into the switch and you may be exceeding the rated current. Does it happen on both high and low beam headlights? You might be able to find a light switch that can handle more current from a vehicle that has 4 headlights instead of 2. As has been mentioned, the easiest thing to do is install relays.
I had the same problem with my Nash going to Vermont, went to Watson street rod work at the NSRA event and he said I needed a relay and after I installed it never had a problem again.
Another vote for putting relays in the circuit. If you are running halogen headlights, they may be pulling more amps than the headlight switch is rated for.
Ok. Yeah it's a brand new switch. No the high beams are a floor switch. That looked like ol the harness was coming out but it's not that. I checked ground behind the light itself and the ground from some loomed stuff near the grill that was grounded. Still doing it. But since it's both head and taillights it leads me to believe what you guys were saying relays. Something is getting hot and throwing them out. The fuse box is warm when it happens. Not super hot but hot none the less. I'll see what goes into putting a relay in the line. Electricity and I don't mix. Oil and water. I can't ever grasp it. I'll see what I can find on the net on it. Or I'll search through the forum for a detailed rundown.
Yes, heat from current as others have noted. Used to happen in my old Cougar after switching to halogen headlights and other old Fords are known for the same thing. Do use relays for the headlights to take the whole lighting load out of it.
Ford rustang era headlight switches do this when they go bad. Cycle on and off in decreasing intervals. I have found reproduction ford headlight switches do this soon after fitting when no relays installed. Posted using the Full Custom H.A.M.B. App!
Mine was doing this too check and make sure the switch can handle the amperage mine was good there but I seemed to have a problem the way things were wired to the switch going out of the switch I had either two or three ring terminals stacked on to p of each other tightened by the nut I took them off wired them all into one larger ring terminal and never had the problem again
Who installed the new switch, new fuse box, new harness? They may have some help and answers too. Relay stops the heavy amperage draw thru the switch. I'm concerned about your fuse panel getting hot. That's not a good thing, actually its vicious spiral. Heat usually means resistance, resistance from too small a wire or too heavy a load. As it gets hot the resistance climbs making it hotter yet. Repeat and around the spiral. As it gets hotter yet the resistance climbs making it hotter yet again. Repeat - eventually shit will melt, blow fuses, or worse catch on fire.
Yes, that definitely merits further looking at. If that panel is getting warm enough that you can feel it, something is not right. As to the headlights and taillights going out, the switch is probably mis-wired. In any switch with a built-in circuit breaker (or even if you have a separate breaker), that breaker is only supposed to operate the headlights; the taillights should be on a separate circuit with their own fuse. Adding the taillights to the headlight load will be very likely to overload it, causing the problem you have. You can add relays to 'fix' it, but the underlying problem will still be there.
You may also find that your headlights are brighter after installing the relay. Good luck.Have fun.Be safe. Leo
One other thing to look at, head light wire size. You may have to increase the wire size to reduce resistance in the head light circuit. Check to see if the wires are getting warm or hot with the lights turned on, if so it's time to bump up the wire size. .......................Jack
Sure sounds like a headlight switch failing to me. Especially since it begins to do it more often once it starts. Maybe a cheap import copy that is defective from the beginning. I'd try a replacement switch first. They're cheap and easy to swap.
get your test light out when it happens again and check the wiring. I've had problems with wiring connections. Mine are on 34s with headlights on a bar. Some bumps can cause the wires to lose connections and suddenly make contact again. You didn't say what year and model car we are talking about.
Oh sorry about not stating the make and model. I am part of another forum/car club and my signature was what I drove and I'm used to it just being there. It's a 1950 chevy fleetline fastback. I was also wrong. It's not the fuse box. It's the switch getting hot. I could've sworn it was the box but I was wrong. I just ran it home about a 20-30 min cruise with the lights on. It's light outside where I am. They went on and off. Got home shut the car off and kept the lights on and I heard the infamous clicking noise. I'm sure it's just a relay or I need to beef up the switch. It's warm to the touch. Checked the box and it feels normal. No heat or anything. Now to look into the relays and installing them.
as usual I know nothing for sure, but if you get desperate - I seem to remember a similar problem that I was told ended up being the floor dimmer switch -which can be prone to rust, dirt etc.
My 59 was doing that and it ended up just needed that back of the switch cleaned and tightened Posted using the Full Custom H.A.M.B. App!
I had a bad dimmer switch once and it only impacted the headlights. If the pedigree of that and the HL switch is unknown, I say replace both. Also look for existing relays under the dash, great if you have a schematic for that car. Bob
The switches have all been updated when the previous owner did the 12 volt swap. The dimmer switch on the floor looks great and they work no problem. But when the headlights go out my high beams won't work. Like I said I'm gonna look at the relay thing. I just haven't had time.
The wiring harness I'm using has a 30 amp fuse for head and tail lights and the switch only had a 20 amp circuit breaker. Tail light were fed thru the breaker as well. I replaced the switch with a "GM" style switch with a separate feed for the rear lights and it took care of my lights out problem, for good I hope.
I had one do that & it was a short in the harness at the core support causing the breaker to kick out on the switch
My 63 Galaxie would do this in the end I fitted two relays , 1 for dip and 1 for main and made new harness for relay to lights as I fitted halogens at same time . No problems at all now . Instead of fuse in line from battery I used fused relay blocks so if main blew fuse I still had dip and visa versa. I used this diagram . Headlight relay wiring diagram by mark & anne's photos, on Flickr
I believe in using relays for headlight circuits. The other big thing in wiring, IMHO, is having enough solid grounds. I rarely rely on the component being wired to have an adequate ground by just it's normal bolting to the body, frame or engine. I add separate ground wires to everything if possible. Good grounding and appropriately added relays will keep away most wiring problems.
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