Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Body Control Unit, interior light relay

Does anyone know if the Body Control Unit (BCU) in the fuse box of a 2014+ Plus 4 GDI has the interior light relay already built into the PCB? even for a car currently without a factory fitted set of interior lights?

I can see the 2 pins (Pin 10 Orange & Pin 22 Orange/Black) on the BCU relating to the interior lights exist and have continuity back to the wire connector's under the dash, however I don't find any earth output from the Orange wire connector. This makes me think the relay is missing, or that some other connection is required to be plugged in?

I also found the Orange and Black wires for the door switch exist and applied an earth connection to see if that solved the issue, however no earth source from the orange wire was found which makes me think the BCU does not have the interior light relay fitted as standard.

On the plus side, I can find a constant live Brown/Blue (+Pos) connector under the dash for the lights. Also, in the case of my car, the door A post is already prepared with a cut out for the door switch

This is schematic for 2014 on Roadster showing BCU driven footwell lights. I would imagine yours would be similar as cable colours and BCU pinouts match.



As you will see either door switch puts a ground to BCU pin 22 which is passed on to LED lights via a timer in the BCU. I doubt there is a relay as such to switch such a low current just TTL circuitry of the timer. The permanent fused positive feed on brown/blue wire completes the circuit to the three LED strips so lights work without ignition key when a door is opened, but just for a time.

Should be an easy retro-fit.

Sometimes I think about some light in deep of the legroom…

But when I order the MOG Sarah (BHM) told me: keep your money, use your mobile… ah.

Than I read this: http://www.talkmorgan.com/ubbthreads.php/topics/719136/footwell-light-cover#Post719136

Now I‘m sure: keep the money and the time of a DIY.

Greets René

On my 2018 plus 4 the BCU controls the led footwell lights, with a timer. The BCU has four relays in it but I don’t know what they are.


In the wiring loom under the tool tray there exists wiring for interior lights which I have used to fit an LED to the rear bulkhead. This simply works on / off with the door switches and seems to be Independant of the BCU

Thanks for this Tim, my LED’s arrived today. Current plan is to have a try over the weekend, which hopefully will be successful 🤔. I was also thinking of putting a light behind the seats so great to hear that the wires exist below the tool tray.

This is confirmed in the Roadster wiring diagram I posted above Tim. As previously said I doubt the +4 is any different in this area.


Good luck with the hookup Kenny, let us know the result.

Tim, could you describe with a little more detail where/how you did this? Maybe some pics? Thanks!

If you refer to wiring diagram second post down, it should tell you all you need to know for adding footwell lights on later models with loom wiring already in place.

I think Tim was just explaning his car has factory fit front footwell lighting. It was the OP KennyW that was interested in an aftermarket fit but it doesn't appear we have had an update

Apologies for not getting back sooner. I found the existing loom wiring, unfortunately I could not get the dimmer to function correctly and ended up simply wiring the earth side of the lights directly to some new door switches that I installed in the A post (NB: door post is already rebated for the switches). Lights work when the doors are open and extinguished when closed.

I also fitted an override switch next to the cigarette lighter socket to allow the lights to work with the doors shut.

Thanks for update Kenny. The BCU doesn't dim the front footwell lights, it simply adds a delay of a few seconds to keep them on after door is shut. Apologies if that is what you were referring to.