drl with high beam

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=114415
Printed Date: May 18, 2025 at 5:11 PM

Topic: drl with high beam

Posted By: dsuperbeat
Subject: drl with high beam
Date Posted: June 12, 2009 at 6:51 PM

Just Wanna know if this will work. I want my drls on the high beam bulbs and I want my high beams to work whether or not my drl switch is on. The switch is so I can turn the drls off if i stop and stay in the car or just don't want them on. The switch will be somewhere in the car

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Replies:

Posted By: i am an idiot
Date Posted: June 13, 2009 at 5:42 PM

What is the resistor for?

Posted By: KPierson
Date Posted: June 13, 2009 at 10:53 PM

I'm guessing to limit current. It better be a big resistor. That 1.2 ohm resistor will allow 6A per bulb - what is the watt rating on the lamps?

A "better" way to do it would to pulse width modulate the high beams. You won't have to worry about finding a >75w resistor to safely do it. I'm guessing on the required watt rating, but I wouldn't be surprised if it was higher then 75w.

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Kevin Pierson

Posted By: KPierson
Date Posted: June 13, 2009 at 10:56 PM

Oh, I just saw the 7.5A fuse - I don't think that will work. The 1.2 ohm resistor will allow 12A to pass through it. If you fuse the system at 7.5A either you will blow a fuse or your high beams won't pull 7.5A. The resistor will reduce the amount of current your high beams consume, but it will NOT reduce the amount of current in the circuit - the resistor will dissipate that difference. If you give me the watt rating of the high beam I could calculate it all out.

You should also put the fuse as close to the battery as possible, NOT coming out of the relay.

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Kevin Pierson