Headlight Relays ARE Worth it! (If done right.)

[CBODY67]

True, but it works in the factory wiring because the total current drawn by the headlights passes thru the switch. The purpose of the relay conversion is to remove that high current from both the switch and the bulkhead connector. As such the headlight switch only passes the minimal current required to close the relays.

Thanks for that verification. I first heard of the GM switches having an internal circuit breaker back in the later '70s when some desired to install aircraft landing lights in place of their existing high beam lamps. Too much juice, so the circuit breaker shut things down.

As for external circuit breakers, the middle '80s GM pickups with power windows use a circuit breaker that plugs in as a normal plug-in fuse might plug in. Male blade terminals, which would be easy to wire into an existing relay-controlled headlight wiring. One for each side? Seems like they were either 30A or 50A? Cad-colored metal, with the amp rating stamped into the narrow top length dimension, along with an appropriate color code stripe.

In the case of external driving lights, some would wire the additional "super high beam" lamps such that they could switch between them with the existing dimmer switch. Of course, the additional lamps would be relay-controlled due to their higher amp draw/additional wattage.

Enjoy!
CBODY67

 

[cantflip]

I

Gerald, I mean this as love and food for thought... but there are a number of things I don't approve of in this thread. I am posting this not only to help you, but to advise anyone else who would follow in your footsteps.

From a safety standpoint, the single pot master cylinder should be replaced with a newer dual circuit... can't help myself, I know you drive this car.

Not an attack, but I hate your wiring. Here are some recommendations to make it better. Solder type battery terminals, to start... the solder plug is installed into the terminal, which is held in a vise and torch heated... then the wire is inserted. Start with a new wire if the old has been trimmed too short. You will fight a never ending battle of voltage drops, trying to keep those cheap bolt on terminals clean and tight enough to conduct current. Up sizing the wire gauge here, especially the ground connection, makes perfect sense.

Any place that requires a crimp terminal, will benefit from a heat shrink type of terminal... I like that they tend to hold the wire more securely too. I know there is a greater benefit from a soldered connection, the shrink materiel is available by itself, should you choose to solder the terminals instead. These should be available nearly anywhere... parts stores, Fastenal, Home Depot, etc.

If you want to really build a safer circuit, use 2 relays and separate the right and left headlamps (low beams). Using a self resetting circuit breaker will, as @Big_John mentioned, provide you circuit protection and a pulsing effect vs no head lamps in the event of a intermittent short/over current situation. Newer cars tend to circuit protect each headlamp individually. Or, you could fuse each circuit from the relay, at a lower amperage than the main power to the circuit, your conductor size could be reduced this way too.

I would also recommend a fuse block that was encased in a plastic housing with a cover..., no point allowing stray metallic objects the opportunity to arc weld...

Wire nuts and this thing...

Would be best avoided by use of a more appropriate splice. Crimp splices are preferable if the wire is too big to effectively solder. I have gutted the metal coil from a wire nut once, where I had to repair a factory splice of 9 wires... I fed a lot of solder into that connection and did my utmost to shrink and seal it from future moisture.

Which brings up this connection...

4 wires coming together like that doesn't seem practical. Either they should be individually fused, or they should be better spliced... sorry, I didn't read back to try to determine why. If a lot of circuits are being added to the car, a bus bar type fuse block may have been a better plan... on single large circuit protector and appropriate wiring to the battery.

The 10 gauge wiring seems overkill for a 30 amp relay too... but I haven't begun to figure out appropriate gauge sizes. IMO, your chief benefit for the improved performance was the high advisable reduction of current through the original headlight switch. The original circuit was not created with the thought of higher current loads from halogen bulbs, and I am far more comfortable with the idea of moving the potential for a catastrophic short from the IP to under the hood. Make certain the headlight switch power is fused appropriately for it's new task of controlling a relay, and it should never fail in the remaining life of your car.

Gerald, you always think stuff out so well... I am hoping you won't be offended by this post, which is half baked and hasn't addressed everything I question (like the garage door hardware). I would be unable to live myself if I said nothing to a member I enjoy reading as much as you, when I saw so much I think could be improved.

p.s. I like using glass fuses as well. My reasoning is I dislike the idea of carrying too big a variety of spares in the car for unforeseen circumstances.

 

[cantflip]

However, I'm going to stick with pigtails have no place in the automotive realm. If you're concerned about splices with connectors or soldered joints, run all new wire for the circuit and do it right. Plain and simple.

What you have now is a fire waiting to happen. Be it 2 years from now or 20, it's huge glaring point of failure.

Bill, I like where you're coming from here. In my experience, splices are a great failure point in a circuit... solder makes a hard spot in stranded wire that will eventually fail like solid core wire from vibration.

On the other hand, pigtails provide a cost effective and reliable way to repair or add to an existing circuit. Most factory recommended repairs involve use of them. IMO, so long as the circuit protection is appropriate and the circuit hasn't been made overloaded... they shouldn't become a fire hazard. The areas of exception would be any wiring that must move as a part of the design... never splice too close to the moving part of a door harness for example... and if the wire has work hardened enough to create problems, be sure to replace enough that your splice replaces all of the stressed wire.

Older Ford brake light switches had the movement problem, and were often spliced too short for an effective repair. They came with a very long pigtail, which was intended to replace the entire length of work hardened wire... and worked fine so long as the tech understood they had to replace all the moveable portion of the harness.

 

[Gerald Morris]

Haven't looked at a Chrysler wiring schematic lately, but isn't there a circuit breaker in the headlight switch (as GM uses), rather than a separate one in that base circuit? When the circuit breaker cools down, light work again, compared to a blown fuse where everything stops until the fuse if replaced.

CBODY67

Yes, the headlight switch has a built in breaker. I'm ordering up the Bussman breakers meant for the 1.25" x .25" form fuse clips. As remote as the chance seems, it would suck if I popped a fuse when maneuvering at night. I've had headlights go out a couple times actually while rolling in the boondocks, Tx and La yrs ago. Then it didn't phase me, but now I have other lives to consider.

 

[Gerald Morris]

I'm not offended. I'll consider implementing the improvements you suggest as time and budget permit. I've achieved my main goal, which was providing ample current to the headlights. I installed the NOS headlights this afternoon, and they give a LOT of light, slightly yellow compared to halogen bulbs. Doubling the number of circuits and overcurrent protection will have to wait, but I probably will pop in 2 breakers for the high & low beams.

I've got the split bolts, rubber tape and gaffers tape now to take care of the bigger junctions, and will barrel crimp connect the smaller ones. I try to make as many of my junctions easily accessible and disassembled as possible, but I also like them to be safe. Heat shrink terminals ARE preferable, when I can get the extra $$ for new stuff in my horde. I make my own wires nice and long, as its always easier to cut them than stretch them. I have a decent supply of #4 for the engine block ground.

I really don't have much trouble w the cheap battery terminals, though good ones are desirable. My one big complaint about them is that they stretch too quickly. I LIKE clamping down the conductors on the terminal. In time, with more circuit hardware, a solder plug terminal might be chosen, provided I can easily attach to it at least one good auxiliary lead to a junction block for the (+) side. The original fuse box has rust/corrosion on most of the contacts too, so replacing it and much of the main runs that weren't replaced when my alternator short of 3 yrs ago forced me to partially rewire the heavy current stuff then. has precedence, barring catastrophe. Aside from one nuisance in the instrument lighting, which has been 12V for 3 yrs now, the wiring has been the LEAST of my headaches.

Aside from my most egregious sins (wire nutted big junctions, the unprotected hot lead and 1 - pop fused headlights) I'm constrained to let the rest of things ride as they now are. I thank you for the wealth of DETAILED INTELLIGENT CRITIQUES AND SUGGESTIONS. I have the damned steering gear box coming up Turkey Day. I shot my $$$ on the replacement box, idler arm and coupler.

So I'll better protect my exposed conductors w ample dielectric grease, torque down my split bolts to spec on the junctions, secure things nicely and call it "done" for now. Then I have to go chase dollars again. Yes, the single pot master cylinder is a source of concern, but for now it works very well with the overhauled front brakes. Mathilda stops nice and quick, and WAS stopping straight until the last couple weeks. I'll be on the ground w that **** soon enough and can twiddle the alignment again after the new box is installed. I HAD to get something. The old one is pouring. Maybe next year, a Borgeson box will be installed, but fopr now the BBB stuff looks OK. At least they have a U.S. plant.

Gerald, I mean this as love and food for thought... but there are a number of things I don't approve of in this thread. I am posting this not only to help you, but to advise anyone else who would follow in your footsteps.

View attachment 230276 From a safety standpoint, the single pot master cylinder should be replaced with a newer dual circuit... can't help myself, I know you drive this car.

Not an attack, but I hate your wiring. Here are some recommendations to make it better. Solder type battery terminals, to start... the solder plug is installed into the terminal, which is held in a vise and torch heated... then the wire is inserted. Start with a new wire if the old has been trimmed too short. You will fight a never ending battle of voltage drops, trying to keep those cheap bolt on terminals clean and tight enough to conduct current. Up sizing the wire gauge here, especially the ground connection, makes perfect sense.
View attachment 230277 View attachment 230278
Any place that requires a crimp terminal, will benefit from a heat shrink type of terminal... I like that they tend to hold the wire more securely too. I know there is a greater benefit from a soldered connection, the shrink materiel is available by itself, should you choose to solder the terminals instead. These should be available nearly anywhere... parts stores, Fastenal, Home Depot, etc.
View attachment 230279

If you want to really build a safer circuit, use 2 relays and separate the right and left headlamps (low beams). Using a self resetting circuit breaker will, as @Big_John mentioned, provide you circuit protection and a pulsing effect vs no head lamps in the event of a intermittent short/over current situation. Newer cars tend to circuit protect each headlamp individually. Or, you could fuse each circuit from the relay, at a lower amperage than the main power to the circuit, your conductor size could be reduced this way too.
View attachment 230280
I would also recommend a fuse block that was encased in a plastic housing with a cover..., no point allowing stray metallic objects the opportunity to arc weld...

Wire nuts and this thing...
View attachment 230281 Would be best avoided by use of a more appropriate splice. Crimp splices are preferable if the wire is too big to effectively solder. I have gutted the metal coil from a wire nut once, where I had to repair a factory splice of 9 wires... I fed a lot of solder into that connection and did my utmost to shrink and seal it from future moisture.

Which brings up this connection...
View attachment 230282
4 wires coming together like that doesn't seem practical. Either they should be individually fused, or they should be better spliced... sorry, I didn't read back to try to determine why. If a lot of circuits are being added to the car, a bus bar type fuse block may have been a better plan... on single large circuit protector and appropriate wiring to the battery.

The 10 gauge wiring seems overkill for a 30 amp relay too... but I haven't begun to figure out appropriate gauge sizes. IMO, your chief benefit for the improved performance was the high advisable reduction of current through the original headlight switch. The original circuit was not created with the thought of higher current loads from halogen bulbs, and I am far more comfortable with the idea of moving the potential for a catastrophic short from the IP to under the hood. Make certain the headlight switch power is fused appropriately for it's new task of controlling a relay, and it should never fail in the remaining life of your car.

Gerald, you always think stuff out so well... I am hoping you won't be offended by this post, which is half baked and hasn't addressed everything I question (like the garage door hardware). I would be unable to live myself if I said nothing to a member I enjoy reading as much as you, when I saw so much I think could be improved.

p.s. I like using glass fuses as well. My reasoning is I dislike the idea of carrying too big a variety of spares in the car for unforeseen circumstances.

 

[Gerald Morris]

I never list them on any websites -- but I figure I might as well add on to your mention of head light relays ----
I have plenty of New Old Stock Head Light Relays -- Both single and Double -- and 6 volt & 12 volt !!!!!!!!!!
All very very U.S.A. made --- no Portugal, no China, from back in the day of QUALITY!!!!!!!!!!!!!!!!!!!!!!

Good stuff! That's why I installed the NOS headlights after doing this job. OooooH the light they give now is lovely AND plentiful. The GE 4001s are Canadian made actually, but the Westinghouse bulbs sold under the Union Carbide EverReady brand are U.S.A. made. Dig the pics below:

If I could have FOUND U.S. made light sockets, I would have got them. THOSE were the only thing sino-made in this particular job. I don't mind Portugese working under Bosch supervision making my relays, BUT, for future concerns, if you have some primo-american stock, I'll haply relieve you of some for fair exchange. I have a case of the Westinghouse lamps BTW....

 

[Flo]

Hello all,
I am currently planning a similar mod to my car, but would like to do a somewhat cleaner "plugin-version". I feel this is really needed, because I have to run H4 headlights over here instead of the sealed beams, which almost double the current.
For this to be really "clean", I need some 3blade connectors, which Mopar used for their headlights. Any idea, where I could buy those? Would need male and female sides for how I would like to do this.
Greets
Flo

 

[Gerald Morris]

Hello all,
I am currently planning a similar mod to my car, but would like to do a somewhat cleaner "plugin-version". I feel this is really needed, because I have to run H4 headlights over here instead of the sealed beams, which almost double the current.
For this to be really "clean", I need some 3blade connectors, which Mopar used for their headlights. Any idea, where I could buy those? Would need male and female sides for how I would like to do this.
Greets
Flo

View attachment 230962

View attachment 230963

You can order them from this sino-vendor I used:

2 x Ceramic Female H4 Headlight Socket Plug Kit w/ Terminals fits 7” Round Lamps | eBay

The ceramic socket and silicon boot are good, though the female slide connectors are flimsy. They should do so long as you don't diddle w the lights much.

DO use 10 gauge (~2.6 mm) wire if you're going to run high current modern bulbs. I pray I'm never legally compelled to to do so here, but sometimes "progressives" seize the government and make laws "for public safety" which empty our pockets yet more than the usual fascist puritans who just let us sweat and die. If such occurs, then I have a harness which will support high current demand.

While 10 gauge seems excessive, the result justifies the expense (in copper). See if you can find some vendor who will indulge you in custom harnesses. My own rough and ready approach doesn't appeal to most folks, but I very seldom suffer for it. (Not never though. That's why I like to have my work reviewed here!)

I pray your job satisfies you when done. THAT is paramount.

 

[tbm3fan]

Hello all,
I am currently planning a similar mod to my car, but would like to do a somewhat cleaner "plugin-version". I feel this is really needed, because I have to run H4 headlights over here instead of the sealed beams, which almost double the current.
For this to be really "clean", I need some 3blade connectors, which Mopar used for their headlights. Any idea, where I could buy those? Would need male and female sides for how I would like to do this.
Greets
Flo

One more time...
BEST QUALITY H4 / 9003 High Temperature Headlight Socket / Plug / Connector. We Welcome Custom Orders! All of our Head Light Sockets / Plugs / Connectors are made with USA Wire! - Innova Design & Dist. Inc. (909) 971-0000

 

[Yeahrightgreer]

Returning to my question about fuses vs breakers. Picture this, you are driving a winding road at night, in the rain with zero traffic and no moon. All your lights are on and you are happily zooming along in your bubble of light. Now a wire bounces against a sharp edge and causes a momentary short circuit. Two scenarios, your fuse blows, all light is gone, your night vision is gone and you freak out trying to see and hoping the road stays straight long enough to get stopped. The other scenario, your breaker cycles letting you know there is a problem while giving you enough light to safely stop and get off the road safely. The breaker solution is actually built into your headlight switch but is defeated when you switch the load to relays. Pretty well all cars have used headlight breakers for years. Super modern cars use semiconductors as breaker/relays to control all external lighting.

Sorry about the thread digging haha. But I’ve had this exact scenario happen!

I had just bought a new old car, an old Thunderbird. I decided to drive it home after the purchase, about 4-5 hours away. It was starting to get late at night and I was trying to crunch time so I decided to pick up the pace.

I’m flying down winding, curving country back roads, no other cars on the road, no street lights to think of and suddenly BANG, headlights dead.
My heart stopped for a moment. Thankfully it was a very starry night with a full moon. After maybe a full 2 seconds the headlights flicked back on.

It ended up being the headlight switch that would start to burn out if left on for more than a few hours. If it had been a glass fuse, I’d of been boned trying to slow down and hang on to the road.

 

[Gerald Morris]

Sorry about the thread digging haha. But I’ve had this exact scenario happen!

I had just bought a new old car, an old Thunderbird. I decided to drive it home after the purchase, about 4-5 hours away. It was starting to get late at night and I was trying to crunch time so I decided to pick up the pace.

I’m flying down winding, curving country back roads, no other cars on the road, no street lights to think of and suddenly BANG, headlights dead.
My heart stopped for a moment. Thankfully it was a very starry night with a full moon. After maybe a full 2 seconds the headlights flicked back on.

It ended up being the headlight switch that would start to burn out if left on for more than a few hours. If it had been a glass fuse, I’d of been boned trying to slow down and hang on to the road.

Yes, I've had headlights actually go out and stay out while driving on some county roads in Johnson Co. Tx many years ago, in a 1970 Mustang Grande', a luxury sort of Mach I if you will. I still have the same 20/10 vision I had 40 yrs ago, Deo gratias, and if it was just me, I'd remain content w glass fuses now.

But, I have other hostages to fortune, so I got a pair of 30A breakers to play things safe for them. My NEXT safety update will be to get a 1967 dual pot master cylinder for MANUAL brakes, as I DON'T like brake boosters, which rely on manifold vacuum. Mind you, brakes work GOOOD for now, but having the prospect of ANY failure meaning TOTAL failure compels a remedy. NOW if El Nino will stop pissing on us here, I can get some work done.....

 

[Yeahrightgreer]

Ain’t nothing wrong with a good set of manual brakes. A good work out. Also don’t have to worry about the booster going out or losing vacuum.
I’m surprised single pot MCs even made it that far into the 60s. No bueno.

 

[67Monaco]

Bill, I like where you're coming from here. In my experience, splices are a great failure point in a circuit... solder makes a hard spot in stranded wire that will eventually fail like solid core wire from vibration.

On the other hand, pigtails provide a cost effective and reliable way to repair or add to an existing circuit. Most factory recommended repairs involve use of them. IMO, so long as the circuit protection is appropriate and the circuit hasn't been made overloaded... they shouldn't become a fire hazard. The areas of exception would be any wiring that must move as a part of the design... never splice too close to the moving part of a door harness for example... and if the wire has work hardened enough to create problems, be sure to replace enough that your splice replaces all of the stressed wire.

Older Ford brake light switches had the movement problem, and were often spliced too short for an effective repair. They came with a very long pigtail, which was intended to replace the entire length of work hardened wire... and worked fine so long as the tech understood they had to replace all the moveable portion of the harness.

Sorry for the Necro post

By pigtail I'm referring to the wire nuts.

 

[Gerald Morris]

Sorry for the Necro post

By pigtail I'm referring to the wire nuts.

Yes, such is trade lingo. 3M "Scotchlock" wire nuts are deemed automotive suitable, and I'll doubtless upgrade the Ideal nuts I currently use with them weather permitting....

3M™ Electrical Spring Connector 512-KEG, Red, 22-8 AWG, 25000 per Keg | 3M United States

 

[70bigblockdodge]

When you crimp your terminals. force some grease into the wire end, multi strand wire with many small strands will wick moisture up into the wire and start corrosion

Thank you, thank you, thank you, thank you, thank you........

 

[1970cat]

scotchlocks are not good connectors. you are cutting the wires by crushing the ends (coating and strands)with the blunt connector and forcing the electricity to flow through a bar which is not specific to the wire gauge. i know a lot of people use them but i have had nothing but trouble due to moisture and vibration. i now remove every one i come across.