Headlight Relay Install
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Headlight Relay Install
Was reading the article on onstalling relays to power the high and low beams. The way the article is written seems to look like the power to the lights would stay on all the time???? Would in not seem right to run a wire from the battery to the relay, then take the wire that powers the light from the headlight switch to the other relay connector, then the output from the relay to the light?? That way the switch is not bypassed. Or am I reading that schematic and article all wrong? I plan on installing the relays on my truck, so I'm trying to clear this up.
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From: Virginia
Is this the article you are looking at?
https://www.ford-trucks.com/article/...r_Brights.html
Here's the diagram from that article.
Power will not flow from #30 to #87 unless there is power at #85.
The big circle in the box is a coil. When power is applied to #85, it flows through the coil to #86 which is ground. This makes the coil a magnet, which mechanically pulls the contacts shut. The contacts are the two side by side lines right above the circle.
https://www.ford-trucks.com/article/...r_Brights.html
Here's the diagram from that article.
Power will not flow from #30 to #87 unless there is power at #85.
The big circle in the box is a coil. When power is applied to #85, it flows through the coil to #86 which is ground. This makes the coil a magnet, which mechanically pulls the contacts shut. The contacts are the two side by side lines right above the circle.
Last edited by Franklin2; Sep 24, 2005 at 10:47 PM.
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Understood!! That makes more sense!! Only once the headlight switch or high beam is turned on the circuit closes, and power flows!! Thanks, I guess I just needed that little extra kick to see how it works!!!
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From: South TX
Brighter Lights = Shorter Life
The concept of this article (and many others just like it, found elsewhere), is solid. In most cases it will make the headlamps brighter. But it will greatly shorten the life of the bulbs.
Most of the bulbs on the market are rated at 12 volts, though there are a few rated at 12.8V or 13.0V. There rated brightness and life expectancy is based on this voltage.
As most vehicles today "run" at 13.5-14.3 volts, this like 10-15% above there rating.
Incandesant (particularly halogen) bulbs don't do well with this. I want to say something like a 1% increase in voltage = 10% shorter life.
The undersize factory wireing produces a voltage drop that keeps the bulbs closer to there rated voltage.
Now, I'm not saying you shouldn't do this mod. If done right, it should make your headlights brighter, but cary spare bulbs and be prepared to use them.
JMHO -Rob-
Most of the bulbs on the market are rated at 12 volts, though there are a few rated at 12.8V or 13.0V. There rated brightness and life expectancy is based on this voltage.
As most vehicles today "run" at 13.5-14.3 volts, this like 10-15% above there rating.
Incandesant (particularly halogen) bulbs don't do well with this. I want to say something like a 1% increase in voltage = 10% shorter life.
The undersize factory wireing produces a voltage drop that keeps the bulbs closer to there rated voltage.
Now, I'm not saying you shouldn't do this mod. If done right, it should make your headlights brighter, but cary spare bulbs and be prepared to use them.
JMHO -Rob-
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From: Easton,Ks
If you were worried about bulbs you could always put a small high watt resistor at the relay contacts.
The relays would also make the switches last much longer and if you do not have one, a relay for the running lights would be nice especially if you pull a trailer.
But then you could go on and on like turn signals, brake lights etc.
Note that the one for the brake lights could mess up the speed control.
The relays would also make the switches last much longer and if you do not have one, a relay for the running lights would be nice especially if you pull a trailer.
But then you could go on and on like turn signals, brake lights etc.
Note that the one for the brake lights could mess up the speed control.
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From: Oregon
Originally Posted by Ultraute
I want to say something like a 1% increase in voltage = 10% shorter life.
Most electrical things automotive are engineered to work at about 10.5 to 15 volts. I think the headlight relay fix is worthwhile.
Just for fun I've put 1157 bulbs, (standard taillight bulbs), on the power supply at 30 volts and they get really bright! For a while..
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From: Easton,Ks
Originally Posted by Howdy
I think you mean for every 1 volt increase ~ 10% shorter life...
Most electrical things automotive are engineered to work at about 10.5 to 15 volts. I think the headlight relay fix is worthwhile.
Just for fun I've put 1157 bulbs, (standard taillight bulbs), on the power supply at 30 volts and they get really bright! For a while..
Most electrical things automotive are engineered to work at about 10.5 to 15 volts. I think the headlight relay fix is worthwhile.
Just for fun I've put 1157 bulbs, (standard taillight bulbs), on the power supply at 30 volts and they get really bright! For a while..
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From: Oregon
Yep, heat's got a lot to do with it. Take the white running/driving lights on the newer Chevy pick-ups. What they did was take a standard brake light bulb and give it a higher temp plastic housing, (and increased the price by 4X). The filaments for your marker lights are a little dimmer than the brake lights, not only so they are easier to see, but because they have an increased duty cycle and they need to last.
Because Chevy uses a bulb with a momentary duty rating full time, they don't last long.
A lot of this stuff isn't engineered to exacting specs and they go with off the shelf.
Because Chevy uses a bulb with a momentary duty rating full time, they don't last long.
A lot of this stuff isn't engineered to exacting specs and they go with off the shelf.
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