DRL's better than lights for MPG?

Read this today in my manual:
"Compared to turning on the headlights, the daytime running light system
offers greater durability and consumes less electricity, so it can help
improve fuel economy."

Seriously? Is there any truth to this?


Ran across this today when I noticed my lights didn’t turn off after locking the truck. Actually, walked into work (for an hour +) then my worried mind told me to go back and sure enough, lights were all still on.

Maybe I’m losing my mind but I thought I’ve been leaving my full head-lights on all the time, locking the truck and they would go off. Then today, they didn’t.

Which is why I broke out the manual and read the above. I don’t see how running more electrical devices reduces MPG but, I’m willing to learn…

I then switched my light switch to the little o, for DRL. Sure enough, the blinkers and such are all lit. Then oddly enough, when I locked the vehicle, the DRL’s did NOT go off. Waited about 10 minutes and they were still on. Had to rotate to off, close/lock vehicle, turn back on and put into DRL mode. THEN, they went off when I locked it. Really odd.

 

I guess in theory it would since its less draw on the electrical system to just run the DTRL vs. the head lights, which means less stress on your alternator.

But I can't see it making enough of a difference that you'd notice the extra cash in your pocket.

 

switch to all leds. the power drain on a quality set of leds is one 20th that of a filament bulb in the same size.

i switched over every single filament bulb on my truck to putco. neutrons but, i don't think it will ever really equate to any measurable savings in fuel.

 

Nothing's free, the energy to power your lights comes from your fuel. That being said it's on the order of fractions of a horsepower.

 

Agreed.

So I wasn't crazy, ALL the lights do shut off when you remove key and open the door, not just the DRLs.

However, I think if you park it, Turn off lights, remove keys then turn on lights, they will stay on. Even after locking truck from outside.

It's quirky.

 

I leave my head light switch on almost all the time. When I shut the engine down and open the door the lights go off. If by chance I turn the lights off and then back on after I've done the above the headlights will go out in a few hours when the battery is spent.
It's always worked that way on my Tacoma. The manual says that but not as clearly as I'd like it to read.
I haven't killed my battery yet but I'm sure one day it'll happen.

I don't have DRL so I use the headlights most of the time. I can't believe anyone could measure the fuel used to power the lights for a few miles.

 

As long as your blinker fluid is full you should be fine and shouldn't worry to much about the drain of power and mpg's from electric devices.

 

I think the gas station pumps have a wider tolerance for metering fuel, especially since they adjust the numbers for temperature (volume corrected to 60F or something).

 

Takes the same energy to spin the alternator with lights on or off, must be a goberment study to claim that.

 

this. i found out the hard way with a dead battery a few years ago. leave the switch turned to headlights. it will turn off when you need it to and you dont have to worry about it.