Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Fog Light Wiring

I think by blowing the fuse might indicate that it doesn’t have its own relay?

Re increasing the 7.5A fuse, there is another consideration. It looks like the infamous dash pcb also handles power from the same fuse via the dash sub harness connection. In the event of a failure elsewhere wouldn’t you be exposing the pcb and traking to the higher current?

Sorry Rog but in the course of this thread have examined wiring from battery to foglights and there is no current involved running through PCB. There are however a total of four fuses (including main battery one) though and as you have surmised no relay.

I'm a great believer with electrics of avoiding unnecessary complexity and in so doing adopting the KISS principle. My Land Rover has survived for approaching 60 years with only one fuse and no relays! Admit to fitting new loom though due to insulation degradation

I agree Richard re the pcb not driving the fogs and if it was just a lighting circuit the fuse adjustment would be fine. But doesn’t the 7.5A fuse also protect the dash illumination that is handled and managed by the pcb? So in the advent of a fault on the pcb or dash illumination wiring, wouldn’t a bigger fuse expose the pcb and its connectors to a current that it was never designed for?

If only Morgan had skipped the £752 + vat pcb and kept it simple like your old landy….

I used to have an ex MOD S3 109".

You could remove all the fuses and everything would still work

As mentioned already the fog light current has no impact on PCB. Furthermore current is not determined by fuse rating. If the PCB demands current beyond its design parameters it's stuffed anyway.

Thanks everyone

TBH the issue here is I'd wrongly assumed all of the group of three wires were all involved in the fog light circuit and one of the red ones was serving as the ground, no wonder I cant get the LED in the switch to illuminate, I really should test with my meter first

So if I've understood correctly the switch should be wired as follows:

* Terminal 1 (Power) = The red/orange wire

* Terninal 2 (Accesory, in this case my fog lamps) = The blue/yellow wire

* Terninal 3 (Ground) = That I will need to create, rather than expecting one of the red wires to serve that role

Hopefully thats correct?

I'll get a set of mini fuses and replace my 10a fuse 12 with a 15a fuse as recommended by Richard.

Thanks again, Dave.

Taking my lead from Doug's terminal reference that sounds spot on Dave

Those two similar cables should both be red/orange colour code i.e. feed from r/h sidelight circuit, in that area. Maybe loom maker was a) colour blind or b) had to switch reels and what you describe as yellow tracer is a pale shade of orange . I would use one that is most obviously red/orange. FWIW red/yellow is used to identify rear fog light feed.

TBH I stared at the two wires long and hard Richard as they're very similar, but to me one is red with an orange tracer while the other is red with a yellow tracer.



To keep everything exactly as you've indicated I will use the red/orange on terminal 1 (power) and fit a 15a fuse to location 12 in the board.

I now just need to find a convenient point to pick up a reliable ground for termianl 3 on the switch .

So to conclude, I took the ground for switch terminal 3 off the currently unused map light circuit, I simply made up a short 7" ground lead with male spade at the map light end and a female spade at the toggle switch end.

With the side lights on, the LED in the switch now illuminates when I light up the fogs so everything is working exactly as it should

Here's where I fitted the Durite toggle switch, I wanted it to be discrete.



Perhaps easier for you to spot with it on?



Nice easy access too.




And with a satisfying tactile click the fogs are on.



Let there be light



Thanks again for everyone's help, especially Richard, I had fully intended to lay a dedicated sub loom for my Marchal fog lights but using the existing wiring hidden in the Morgan loom definitely made for a much neater OEM job. I'm very grateful for all your encouragement to press on with the factory front auxiliary lighting circuit, TBH I would never have even known it was in there without Richard pointing it out, in summary I highly recommend anyone else considering fitting front spots or fogs makes use of this circuit.

Merry Christmas to you all

Good to see a happy conclusion 😄