I'd be very surprised if the wiring and circuit I've used doesn't include a relay, afterall the wiring has been put there in the loom with the specific purpose of running front auxiliary lighting.

I'm also comfortable the circuit is safe as its clearly protected by fuse 12, and while the load did blow the 7.5a fuse this was actually a good safety test and we now know the circuit happily runs with a 10a fuse too, so its not like there's excessive load on the circuit and 10a seems to support my calculations.

As we know, amps = watts / volts, so that would be 55w / 12v = 4.59 amps x 2 lamps = 9.18a

My Marchals are rated at 55w each so it's no wonder the 7.5a fuse (fuse 12) blew, upping it just 2.5a to a 10a fuse worked supporting my calculations but at just 0.82a over the predicted load it's a little too close on the fail rating for my liking.

I'd prefer to run a 12a fuse instead which gives a safe margin of 2.82a over calculated load and is still only a 4.5a increase over the 7.5a fuse originally designed to just protect the O/S side lights.

I'm comfortable with the circuit now that only works with the car's side lights on exactly as you'd expect, I will up my fuse 12 from 10a to 12a but that's all it needs to complete the project and make the circuit both safe and reliable.

[Linked Image]

The setup includes 20,000 lumen 3000k (traditional halogen colour) LED H4s under yellow glass globes for the headlights, supported by beautiful period chrome Marchal fog lights running yellow traditional incandescent 55w halogen bulbs. The light output is outstanding especially as I've chosen to go yellow, the cutoffs are really sharp so while some adjustment is needed I'll sort this after marking up and then copying what my 2021 Toyota C-HR projects on my white garage door.

However, I'd still like to get my illuminated toggle switch to light up.

To explain how I've wired the up the lamps currently, firstly I'm grounding my Marchals from lamp to chassis rather than tapping into the headlight grounds as recommended by Richard, secondly I couldn't find the blue/yellow wire on the N/S so ended up just extending the O/S blue/yellow wire across the car to power the N/S lamp.

This all worked out fine, but I suspect its also why I've got no power to the switch LED. thinking


Last edited by Montegue; 08/12/22 07:24 AM.