While Richard's existing wiring option seems by far the best way to proceed, if it does turs out my loom wasn't built with the blue/yellow wires here's another logical approach from Jon (CooperMan), although as I'm powering fog lights I'd be triggering the additional relay from the dip beam circuit not the high beam circuit as Jon has correctly used for his driving lights.

Like Jon I have no aircon, so that 30a fuse protected feed would make a logical choice to repurpose for the high amp +12v supply for my fogs, I have the aircon switch in my dash so I assume if I'm repurposing the aircon fused circuit I could also turn on my fogs with this switch? However, to ensure I blow the fuse before I overheat my additional fog light wiring I would have thought replacing the 30a fuse with a 20a fuse would be more appropriate.

Originally Posted by CooperMan
John, just checked my old S1 wiring diagram and as suspected there are no fuses or cables marked up as Aux lights

I used the 30amp Aircon feed to the 8 way bulkhead fuse box (as I had no aircon) mounted a relay below & took the 'trigger' wire off high beam, worked well

Andy MOT, may be able to confirm but my MOT chap said if linked to hi-beam, the spot lamps did not need testing for aim, if on a separate switch they did (as the driver could leave them on)


I found the above here....

http://www.talkmorgan.com/ubbthreads.php/topics/555419/2018_Roadster_fog_lights

Either way I’ve now completely moved on from my original assumption that I’d be using the stalk switch, my new fog lights will definitely need a separate auxiliary switch to control them. Hopefully I do have the blue/yellow wires as it seems Morgan built this circuit into the loom to make exactly what I’m trying to achieve a straightforward and safe exercise for their dealers looking to retro fit additional lighting to a customer’s car.