Guide for fitting DRL’s to MX-5 Mark 3.5

Technical Area Electrics & ICE
2

I’ve just fitted some Eagle Eye LED DRL’s to my MX-5 Mark
3.5 and I’ve put together this guide, with acknowledgments to the other write
ups which gave me a head start.

Wanting to have an installation that could easily be removed
this installation does not involve any modifications to the vehicle thus if
removed it would return to the original state.

The primary challenge is finding a suitable power supply.
Most DRL control modules require an ignition positive feed and a positive feed
from the lights, together with an earth. In this situation I wanted the DRL’s
to stay on with the sidelights but go off when the headlights were on.

The easiest place to take the power supply from is in the
engine compartment main fuse box. Remove the black cover, and then free the top
fuse tray by undoing the latches around the periphery.

 

There
is no need to undo the two bolts connecting the positive supply to the top
tray. However these cables do restrict the movement of the tray so to increase
the accessibility loosen the cable retainers for these 3 cables.

 

 

With these free the whole tray can be swung up to expose the
underside.

Two power supplies need to be found. The ignition positive
bus bar is highlighted below:-

 

 

 

As there is no spare fuse slot connecting to this bus bar I
took the power supply from this side. A flat blade terminal connector can
slide, with some firm pressure, alongside this bus bar without damage - red cable in the image.

 

 

 

The next positive power supply is for the headlights. There
is a smaller bus bar supplying power to the 3 headlight fuses.

 

 

 

The red cable is connected to the 2 fuses either side so
that all 3 fuses are supplied with a positive feed when the headlights are on.
Again a flat blade terminal can be slide firmly alongside the bus bar - white cable in the image.

 

 

Both of these connections are firm and would take a pair of
pliers to remove.

The final connection is for the earth. The nearest earth
point was the bolt holding the fuse box compartment.

The new red, white & black cables all exit the fuse box via the same exit as the main cable bundle, with the DRL module being mounted outside of the fuse box.

 

 

The DRL module itself was fixed to a spare hole in front of
the main fuse box.

 

 

 

Finding DRL’s to suit the front of the Mark 3.5 and look
discrete has been a challenge. I fitted two 3W Eagle Eye LED’s either side of
the license plate holder, bolted through the grille so no drilling was
required.

 

The cables to the LED’s from the DRL module drop vertically
downwards (shine a torch up from below to see the space) into the space behind
the front bumper & grille.

To access this area the plastic guard will need at least
loosening where it meets the front lower bumper.

I used AMP Superseal waterproof connecters, wiring tucked up
behind grill.

 

 

Final result:-

 

 

When lit they are much brighter than in this photo (taken
with a flash):-

 

 

Hopefully these will increase the visibility of a small grey
car!

 

 

 

 

3

Good effort. Not for me though tbh. It would be nice if these led bulbs could replace the sidelight bulbs within the headlight unit. Do these only look bright from straight ahead as I think the sidelight bulbs point at an angle away from front on.

4

Fair enough. I’ve replaced the sidelight bulbs with LED’s - the brightest I could find. It’s not the angle into the reflector assembly that matters per se - it’s the shape of the reflector assembly that determines how bright (or not) the sidelights appear. These DRL LEDs are dome shaped thus the light spreads out in all forwards directions in a very bright but unfocussed manner - which does make them ideal for DRL’s.

5

G’day Rob

Great project, but I have a couple of issues.

Those crimp connectors are not designed to be used in this fashion.

Where’s the fusing, your going straight off a 12 volt bus bar, if something shorts you will have some great fireworksWink

6

Good write up Rob. My concerns too would be in taking the pos supply like that, you should be able to find suitable wires to splice and solder. The earth should not be clamped down onto plastic, any spare hole, or a small drill and self tapper, could be used with the paint removed properly.

I’d like to use the existing front fog lights, possibly with different bulbs. Anyone done this?  I’ve not looked at it but there should be a way to change the switching.

 

7

Thank you for your comments.

In response - I know - but they work very well in this situation and can be removed without damage to the vehicle.

The DRL module has an in-line fuse on the power cable (not shown as I assumed that this would be obvious).

8

The primary goal here was an installation that could be removed leaving the vehicle in its original condition.

Thus the arrangement of the power cables - any of the wires coming from the bus bars could be used but (a) they would be after the fuse (and the DRL module has its own in line fuse) and (b) these wires are very thin.

Same with the earth - the bolt - with a washer beneath it - is a satisfactory earth.

The fog lights can be used as DRL’s and there are a number of good posts for going down that route. However I wanted to keep the factory fitted fog lights for their intended function.

9

@richm I did this in the front fog lights by a simple wiring mod in the relay box. Got a few posts suggesting I’d broken quite a few legal light regulations so put it back to standard.

10

 

 

Thanks, what was the problem, is it just that the lights need to be marked RL, can’t see anything else here, http://assets.dft.gov.uk/publications/dft-information-sheets/daytime-running-lights.pdf

1 Like
11

Pm sent (well in a minute anyway)

12

Although three years on, this has proved invaluable for me to complete the installation of DRL/Foglights. I purchased a pair of OEM Foglights blanking grilles from MX5 parts at £5 each side which I thought was excellent value. I then purchased a pair of China’s finest fog lights with halo light surrounds and a DRL control module. Bought them from a land rover spares place near to me, have used them before for other lighting. I couldn’t sort a switched live for the DRL module until I read this old thread. An easy fix and everything works perfectly with the DRL’s dimming when side or main lights switched on and fogs controlled by the RX8 stalks fitted by previous owner. Result! The lights themselves, I had struggled to get something that filled the blanking plates, neither too big nor too small and these were perfect! Finished it all off with a set of the ILMotorsport chrome surrounds for the fog lights.

Barrie

13

Thanks for the update 

14

Thank you! I should have said, reading back on my previous post. I had some 4 LED spot lamps fitted to the car when I bought it but they were too big and didn’t look right. The OEM Grill blanks had been modified to accept these larger lights, beyond reusing them. Hence why I bought some more. The new lamps have an approximately 50mm diameter on the face ( including the halo ring ) and are a smaller diameter on the main lamp body. I removed a circle from the grill part off the OEM blanks to allow the lamp body to sit snugly into this aperture from the front and fixed them with some two part epoxy. Now, with the lamp recessed into the bumper and the chrome surround, they look ( IMO ) very smart. Will post up some pics later today!

Barrie

15

Right, a couple of pictures 

First one is the lamps I purchased.

 

Full DRL power next

 

Half power with side lights on

16

Oh, and one more without the light on!

 

17


I’m quite sure it’s illegal to do this for ‘highway use’

 

18

It is not illegal

19

It’s not illegal but DRLs should dim automatically or be able to be turned off in low light conditions i.e when headlights are in use, that’s what our beloved government says.

20

Yep…Otherwise they are too bright at night