How to enable low beams with high beams

[shaggist]

Has anyone been able to connect your low beam headlights to your high beam light, so that, when the highs are on, the lows are also? I can't find out if Ford Fusion have headlight relays, and, if they do, where they are. If you have a non-HID setup, please post how you did it. A lot of Fusion owners need the extra light when driving at night.

[Waldo]

From the 2011 Workshop Manual:

 

Headlamps — Fusion

The headlamp system is a quad-beam pattern system. It consists of replaceable low and high beam bulbs. The headlamp assembly has the park/turn lamp integrated into the headlamp assembly.

If the headlamps are on when the ignition switch is turned off, the battery saver feature turns off the headlamps after 10 minutes have elapsed.

When the low beams are requested (based on inputs to the SJB ), the low beams are illuminated.

When the high beams are requested, the high beams are illuminated with the low beams.

When the flash-to-pass feature is requested, the high beams are illuminated for as long as the multifunction switch is held in the FLASH-TO-PASS position.

 

So it's already done for you.

[shaggist]

That may be what the workshop manual says, but it isn't looking at the front of my car. When I put the stalk in the hi-beam position, only the highs are illuminated, no lows. Does your manual have a diagram or schematic of the headlight wiring system? If so, could you send me a copy of it to my email address. Maybe I can figure out why my car and the manual disagree.

[akirby]

How do you know they're not both coming on at the same time?

[shaggist]

What would be your guess as to how I know? Would you perhaps say I got out of the car and walked around to the front and looked at the lights? If you did guess that, you would be right and win a prize.

[akirby]

I was just wondering if you could actually see the low beam bulb and know for sure that it wasn't on when the high beams were on or if you were just guessing. They should both be on for high beams.

[shaggist]

I offer my apologies to all. When I first looked at the lights, they were in bright sunlight and I didn't bend over to check. The low beams looked to be off. I just went out and checked them, again in bright sunlight, but this time I squatted down and looked directly at the bulbs, and lo and behold, they ARE on. It's a miracle! A visitation from the hand of God! I have 4 lights on at the same time on the front of my car. Halleluyah!

 

Now, has anyone tried adding relays to connect the lights directly to the battery for higher voltage and brighter output? If you have, what was the response, if any, of the SJB-smart junction board. Did it register a fault or abnormal condition of any sort? Any and all input welcomed.

[akirby]

Now you know why I asked the question.

 

First - you don't increase the voltage. It's 12 volts regardless. It's the wattage on the bulbs that determines how much power is consumed. Just like at home changing from a 40 watt to a 60 watt to a 75 watt light bulb. And if you just swap out the regular bulbs for higher wattage bulbs you'll burn up sockets and wiring and other parts. It's only designed for the stock wattage. Some bulbs may work slightly better than others but you don't want to increase the wattage.

Edited July 15, 2014 by akirby

[shaggist]

Let's expand on the thoughts about voltage, amperage, and wattage. The system is nominally 12 volts, and when the motor isn't running, that's the voltage of a fully-charged battery. When the engine is running, the system voltage is increased to 13.2 volts, due to the alternator putting out that voltage to recharge any usage of the battery charge for starting and running the engine. So, increasing the volts to the bulbs from 12 to 13.2 increases the available wattage for the bulbs to draw. I.E.-brighter light emitted from the bulbs. Theoretically. Actually, the small wiring that Ford uses in their lighting circuits caused a loss called voltage drop when the wire gauge isn't large enough to allow all the amperage through that the device can use. So, the voltage that actually reaches the bulbs is more on the order of 10-11 volts. It's kinda like choking a garden hose down in diameter and restricting the flow through the hose. So, if you connect the filaments of the bulbs directly to the battery through wires of sufficient gauge, they can operate at their maximum designed parameters and put out 100% of the light for which they are designed to emit. These wires must run through switches, called relays, and fuses between the relay input and the battery in order to be properly protected from any electrical malfunction. The wires that connect the relays to the bulb filaments are a larger gauge than the wires in the factory circuit, so they are able to deliver the full voltage and amperage to the bulbs and insure their operation at full power without straining and stressing the factory wiring. The factory wires, that run to the bulbs are used to activate the high beam and low beam relays, which draw very little current, thereby protecting the factory circuitry from any stressing. Any questions?

Edited July 15, 2014 by shaggist

[andyross]

Another issue with running both low and high at the same time is HEAT. The buib itself could overheat and shatter. You could melt or otherwise damage the headlight housing.

[shaggist]

The factory headlight setup runs both highs and lows together when the high beams are activitated, so heat isn't an issue with our cars. They are designed to handle the heat load of the H7 and H11 bulbs being both illuminated at the same time.

[Waldo]

The factory headlight setup runs both highs and lows together when the high beams are activitated, so heat isn't an issue with our cars. They are designed to handle the heat load of the H7 and H11 bulbs being both illuminated at the same time.

 

Right, they are designed to handle the heat load of both bulbs at the same time at the voltage supplied through the "choked" wires. Increase the light output of the bulbs will result in more heat. Whether that's enough extra heat to cause damage isn't easily calculated.

[akirby]

Let's expand on the thoughts about voltage, amperage, and wattage. The system is nominally 12 volts, and when the motor isn't running, that's the voltage of a fully-charged battery. When the engine is running, the system voltage is increased to 13.2 volts, due to the alternator putting out that voltage to recharge any usage of the battery charge for starting and running the engine. So, increasing the volts to the bulbs from 12 to 13.2 increases the available wattage for the bulbs to draw. I.E.-brighter light emitted from the bulbs. Theoretically. Actually, the small wiring that Ford uses in their lighting circuits caused a loss called voltage drop when the wire gauge isn't large enough to allow all the amperage through that the device can use. So, the voltage that actually reaches the bulbs is more on the order of 10-11 volts. It's kinda like choking a garden hose down in diameter and restricting the flow through the hose. So, if you connect the filaments of the bulbs directly to the battery through wires of sufficient gauge, they can operate at their maximum designed parameters and put out 100% of the light for which they are designed to emit. These wires must run through switches, called relays, and fuses between the relay input and the battery in order to be properly protected from any electrical malfunction. The wires that connect the relays to the bulb filaments are a larger gauge than the wires in the factory circuit, so they are able to deliver the full voltage and amperage to the bulbs and insure their operation at full power without straining and stressing the factory wiring. The factory wires, that run to the bulbs are used to activate the high beam and low beam relays, which draw very little current, thereby protecting the factory circuitry from any stressing. Any questions?

 

I would buy that if you've actually measured the resistance drop of the factory wires.

 

However - you're still getting a lot more heat from the bulb itself which could melt the sockets or housing.

[shaggist]

There are a number of voltage drop calculators available on the internet. Just Google the term and you'll find them. An example of voltage drop is as follows: a 4 foot length of 18 gauge stranded copper wire with 12 volts applied at one end will show 11.8 volts at the other end drawing 4 amps (48 watts) under normal operation conditions. That is a significant loss through such a short length of wire. The headlight wires in our vehicle are longer than this, having to run from the power source to the fuse panel to the headlight switch to the dimmer switch and then to the headlight bulb.The same 4 foot length of wire in 14 gauge drawing the same number of amps will show 11.91 volts. That's a percantage loss difference between 1.67% and .68%. The larger the gauge, the more efficient the transmission of voltage and current. The additional current available at the bulb will result in a hotter filament and brighter light, but not a corresponding increase in bulb heat emitted. There should be no danger in utilizing 55w bulbs to their maximum capabilities. The danger would come if an 80 watt or 100 watt bulb were substituted. Then thermal damage to the headlight housing would be much more likely.

Edited July 16, 2014 by shaggist

[akirby]

So what gauge wire is actually used? 18 or 14? or 12? That's my question.

 

How do you increase the voltage to a filament bulb yielding more light output without generating more heat?

[shaggist]

The wire gauge in the Ford headlight system is 18 gauge, which is too small for proper current carrying capabilities. It is adequate, but that is all. Supplying the bulb filaments with more voltage and current will result in an increase in bulb thermal output, but not enough to make a difference in the internal temperatures of the housings. There isn't a linear increase in the thermal output in relation to the higher filament temperature. Just accept the fact that it works without problems.

[Waldo]

The headlight wires in our vehicle are longer than this, having to run from the power source to the fuse panel to the headlight switch to the dimmer switch and then to the headlight bulb.

 

The headlamp power doesn't run through the switches, it just comes straight from the SJB (which is on the lower left of the driver's footwell. That means the wire running to the right side headlamp is close to double the length of the one to the left side. So how much dimmer is your right side headlamp compared to the left?

[akirby]

 

The headlamp power doesn't run through the switches, it just comes straight from the SJB (which is on the lower left of the driver's footwell. That means the wire running to the right side headlamp is close to double the length of the one to the left side. So how much dimmer is your right side headlamp compared to the left?

 

Thus my point. While technically there may be differences I don't think they're noticeable at all.

[shaggist]

The whole idea behind my explanations has been to provide information to those who wish to optimize the headlights on the Fusion. Never was it said anywhere that the current setup isn't adequate. It is just not as good as it could be. The data that I have provided is available to any and all on the internet, so that it can be verified. Nothing has been posted that has factually refuted any statement I have made. So, go your own way and I'll go mine.

[akirby]

That wasn't the point. The point was even if you do the improvements you laid out, would the difference be noticeable?

[shaggist]

Why don't you do the modification and find out. Then report here on your findings.

[akirby]

I'm perfectly happy with mine the way the came from the factory.

[BlueOval2010]

Headlight Haiku:

 

too much power flows

hot lamps turn night into day

soon both fade away

[thefoeyouknow]

Vdrop is irrelevant. The SJB feads the low beams a pwm power supply, you'll never get full B+ at the low beams, and if you try to install relays, you'll get bulb out warnings and SJB circuit protect shutdown. So, to summarize, what you're measuring as Vdrop, is the SJB modulating the power supply, not a lack of ampacity in the wiring. What you should be measuring at the low beams is duty cycle, or frequency. Want brighter from stock bulbs? Try a 30v 10000uF capacitor at each. That should smooth out the power and bring ir closer to operating voltage, but for the tiny gains, it's really not worth the work.

 

Also, if you're running voltage is only 13.2, your lights are probably dimming because of your dying alternator. You want 14 to 14.8 while the car is running, and if you have less than 14.4, suspect a cell problem in the battery.

[akirby]

I thought the newer alternators were variable output so they don't necessarily put out 14+ all the time.