Wiring Daylight Running Lights (DRL’s) on a caravan

Someone contacted me asking how to wire DRL’s (Daylight Running Lights) on his caravan. He wanted to attach a strip of super bright white LED’s on each front edge of the caravan so as to make the edges more visible during the day. However, he wanted the LED’s to come on only when the engine was running and turn off when the sidelights of the vehicle were turned on (as is normal for DRL’s on a vehicle) and the other requirement was not to have to make any wiring changes to his tow vehicle.

There was only one way I could think of wiring the LED’s to fit his request. If you are considering doing the same, this is the solution I came up with:-

Daylight Running Lights on a caravan

The LED’s are powered via a suitable fuse from the fridge circuit. This ensures they will only turn on when the engine is running. A relay is used to interrupt this circuit and is activated by the side lights being turned on (Pin 7). I have shown a fuse in this circuit as well. The relay can be any suitable 12 volt automotive relay.

The fuses and fuse holders can be found in most auto-parts stores.

I’m not sure if DRL’s are strictly legal or not on a caravan, but I do like the idea of a LED strip highlighting edge of the caravan when you are towing. Anything to increase visibility has to be good!

I hope this circuit gives you a few ideas.

Here’s the PDF file of the drawing above: Daylight Running Lights on a caravan


Copyright © 2011 – 2016 Simon P Barlow – All rights reserved

8 thoughts on “Wiring Daylight Running Lights (DRL’s) on a caravan”

  1. Neville James said:

    Yes, that’s a possibility, perhaps so that an empty socket isn’t left? I’ll do some more digging on the French Renault forums, but it’s slow going with the language.

  2. Neville James said:

    I’m always interested in your electrical solutions, and particularly appreciated the circuit diagram you sent me for a habitation relay to install in our 23 year-old Lunar.

    This one for DRLs is good, but I wonder whether the original request is valid…? My DRLs (2013 Renault Megane) are on all the time that the engine is running, they don’t go off when the side or head lamps are switched on. This would surely make the job simpler.

    Autumn has arrived here in France!

    • Hi Neville
      I don’t think the implementation of DRL’s across manufacturers is always the same. Some vehicles turn off the DRL LED’s when side lights are turned on, others just dim them. Some vehicles turn off the DRL on one side when the indicators flash to make the indicator more noticeable. Other manufacturers opt to operate rear lights with the DRL’s while others don’t. If you look round there seems to be many variations.

      The original drawing was valid for the tow vehicle being used, and as far as I understand it the rule is DRL’s must be turned off (or dimmed) when the vehicle lights are turned on for night time running… which my solution does comply with.

      Autumn arrived here in the North West too, we are now into leaf scooping season!


      • Neville James said:

        Well now, I owe you an apology!
        I should have done this check first, but being curious after I wrote to you, I went out to the garage to check my DRLs; since it’s usually me who drives I’ve never really noticed what happens, but the DRLs, whilst they’re on all the time that the engine runs, they have a dim mode, so that they’re not as bright when the other lights are on, but revert to full strength when used during the day with no other lights illuminated. I’ve only had the car for 10 months!!!
        So your schema is good!
        One other thing I noticed is that there is a small bulb, which looks like a sidelight, in the headlamp nacelle, but it never comes on, no matter what combination of lights/motor I try. The LEDs (DRLs) act as sidelamps/parking lamps.
        None of this is explained in the handbook of course. The headlamps are xenon so I’ve got multiple spots in front of my eyes as I type now; by golly they’re bright lamps!
        Talking of leaves, we have a huge garden here with many trees and this time of year is “leaf-blower” time. Just now when the leaves are falling thick and fast, it’s also pouring down, so the blower will be useless. Another back breaking job is on the cards!

      • Hi Neville

        I wonder if the small bulb is a ‘leftover’ from the old side lights pre DRL? Bit of a mystery that one!


  3. Cheers Colin 🙂
    It’s nice to know my ramblings are appreciated.


  4. Very good simple way, your spot on in my opinion, I would like to thank you for all the help you give to us caravanners, it must take up a lot of your time,



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