Will running both high and low beams at the same time hurt my Excursion?
 

I can turn on my high and low beams at the same time. Can you?

When the low beams are on and I begin to put ever-so-slight forward pressure on the lever (to activate the high beams), the high beams switch on while the low beams are still on. If I never push the lever "over the hump," the lows will remain on while the highs are on, too. The low beams switch off only after the lever gets "over the hump."

Obviously, this makes driving the back country roads a bit nicer — similar to having fog lights on while high (or low) beams are on. And, I am tempted to run them this way; in fact, sometimes I toggle this on for 10 seconds or so.

My question here is, do any of you smart people KNOW that this will not harm the switch, the lights, or any other electrical part? Or, do you KNOW that it will harm.

Thanks!

I can't give you the definitive answer that you're looking for, but I will say that generally speaking, when you try to get something to do something it wasn't originally intended or designed for, problems usually result.

You can also engage both sets of filaments by pulling the turn signal lever toward you. This "flashes" the high beams but in reality it's just adding the high beams to the mix.

I don't think it would hurt anything in the short term, but if you wired it up so that the low beams were on all the time and then drove around with the high beams on, I wouldn't be surprised to see damage to the relay or headlight switch.

BTW I have the same eagle eye lights, and they are very bright even on low.

Exactly. I should have thought to include this to be sure my explanation explained what I wanted to explanatorize.

About the rest: Right, I am not about to run them this way... unless someone thoroughly explains that it will not, in fact, hurt anything, ever.

My educated guess would be that in doing so for any extended period of time, you will overheat the headlamp assemblies and the Hi/Low switch. There's also an issue of overworking the alternator.

I am pretty sure that this is not legal in any state, except for a short burst to see beyond your low beams. Personally, I would rather have an auxiliary set of driving lamps, wired on their own circuit, for such needs.

You WILL burn out the headlight switch from the amp draw.

Had not thought of this. Thanks!

I believe, the wording in most states is no more than 2 headlights...
this dates back to the good-old days when cars had 4 "headlights" 2 for low AND beams, and another 2 hi-beam only... So you essentially had 4 headlights on when using "high beams".

with single "lights" now - it's pretty impossible for the police to tell the difference between 2 or 4 elements on inside the lens. Of course, having "high beams" on and annoying oncoming cars is a problem of it's own.
:-X03

I do it all the time and for extended periods when off road and camping.

But then I'm warped and from Kali.
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only thing this harms is the switch itself due to the amp draws like mentioned above can still do it but id stop by a junk yard an pick up a spare switch just incase it frys since it isnt to fun being stuck on the shoulder of a freeway at midnight with no headlights at all

Whatever voltage/amperage goes to the lights comes from a relay NOT the switch itself.

The amp draw through the switch is minimal and is only used to engage the relay.

This is a very common mod that people do to the Dodge trucks and it doesn't fry anything (the dodge trucks have their own appetite for blowing bulbs) however like mentioned it is illegal in most states.

Hmm. The plot thickens.

I'm not sure, but I don't think an Excursion uses a headlight relay. I think the full current goes through the headlight switch.

Use relays to make a harness pulling power from the batteries directly. Then add a diode to make hi trigger low as well if you want. Been discussed many times in the 99-16 superduty and the 99-03 7.3 subforums. Lights will also be brighter due to less voltage drop.

I would be more worried about the increased temps inside the headlight housing. As with any engineered mass produced product, you build it only as sturdy as you need it. I would imagine the increased temps of running both filaments at the same time for extended periods were NOT accounted for in the design, and that increased temp could do damage to the headlight bulb itself (as mentioned, most states it's illegal to run both so the bulb designers would only have accounted for minimal time running both) and the headlight housing itself could not be able to handle that much heat for that long.

As others have said, running a 2nd pair of lights in the bumper seems best to me. I have a set of Rigit 2x2's (4 LEDs each) where the factory driving lights were installed...makes a WORLD of difference and I don't have any legal drama to worry about nor heat issues. I wired mine to go off when the high beams are on (sorry coppers, you'll never catch me! HAHAHAHA!!!) so I don't have to worry about it (but of course there is that little hidden swich I have to bypass that for off road fun).