Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Roadster 3.7 Daylight Running Lights

Has anyone fitted DRL to their 3.7 Roadster? I have fitted them to my Plus 4 GDi without any problems. Having now acquired a 2018 Roadster I would like to do the same - the headlights that incoporate DRL LEDs. Looking at wiring diagrams it seems the Roadster uses a CAN network system. Would a DRL module interfere with that? Or as it's only working with the headlamps/sidelights circuit will it be OK.

Any assistance would be appreciated.

Check out thread starting here Les, particularly my last post on it. Some of the links for sources may have dried up but think you have enough info to find others. Fitted them four years ago now and wouldn't be without. Absolutely no MOT issues during that time. Note headlamps also have a permanently on sidelight function.

One important point is that the dual colour LED's must be labelled as CANBUS friendly but only because this means they have same indicator current draw as OE to maintain correct flash rate.

Thanks for that link RichardV6. Reading those posts it seems my 2018 Roadster comes with both front & rear sidelights coming on with the ignition (unlike my Plus 4 GDi). I fitted these headlamps to the Plus 4, but that didn't have the 'always on' sidelights, so I may need to rethink how I do this. I wanted to know if by introducing the DRL module into the electrics it would cause problems with the CAN system.

Yes the 3.7 Roadster has all sidelight feeds on with ignition. No there is no CANBUS monitoring on lighting system bulbs. As said the only issue is when converting from indicator/hazard filament bulbs to LED. The current draw needs to be maintained for the flasher relay within BCU to function at the correct speed. Generally this means the use of CANBUS friendly LED alternatives. This being much simpler than using clumsy external resistors.

I think the new headlights should be ok then as they pick up the sidelight feed for the LEDs. And the DRL module just dims them when the headlights are switched on. I can't say I'm a fan of having the rear sidelights on all the time though.

Believe me Les rear lights provide much needed visibility for following cars during daytime under dull or even slightly misty conditions. If you have ever driven the B1225 road over the Lincolnshire Wolds past Belmont TV mast you'll know what I mean.

I have Cain's LED light conversion which incorporate LED sidelights I just turn on the sidelights when I start up. I like having the rears on for visibility.

Please let me share another perspective Richard

Heat is the number one enemy or killer for LED's. LED life is directly related to temp. After market canbus friendly LED's bulbs are designed to mimic filament bulbs so may have a load resistor poked up the back. Typically the resistor will need to dissipate around 20w. That's an awful lot of heat in a tiny package. For the life claims manufacture's thermally mitigate the heat load using cooling fins on the bulb package, limiting the LED brightness or wattage and calculating life based on a typical shortish indicator duty cycle. However, should you ever need to leave your hazards on for and extended period, all bets are off for the poor old LED's....

This is my chunky 50w load resistor safely dissipating 20w through the metal body work. I checked it after fitting with the hazards on for 15mins. It was way too hot to touch and the temp was still rising.

I'm a fan of rear lights on too. You see so many cars with DRL's on up front in bad weather and nothing at the back. Only auto lights might give this option if fitted and on!

Having been rear ended twice in two different Morgans, its something I have often mused over. I feel that having the rear lights on all the time detracts or reduces the visual impact for the driver on your tail when the brake lights are needed. For that reason, no rear DRL's for me.