DrRMHISF

Does anyone know which fuses are switched live in the engine bay fuse boxes?

I'm wanting to install some OSRAM LEDriving Fog lights and would prefer to have all the wiring in the engine bay rather than head into the cabin.

2URGSE

Fog lights usually come with an On/off switch.....which is usually mounted inside the cabin.

It would be a much cleaner install if you get an add-a-circuit and go into the cabin.

DrRMHISF

I've got an Add-A-Circuit, but I wanted to use a fuse in the engine bay, rather than heading into the cabin. It seems much cleaner to me that way than poking around in the back of the firewall

Htony

No multimeter to check it yourself? There ought to be unused spare slot too.

DrRMHISF

I do have a multimeter, yes. But I also have two children on Xmas break who are very demanding of my time, so I figured if I could short cut the process by tapping into the collective knowledge of existing owners it would help.

I can see some spare slots, but as I haven't had a digital poke around I figured they would simply hold spare fuses and be unpowered. Am I wrong?

Htony

Typically there is powered spare slot which meant to be used for higher option of something like that. If you really don't find one,
you can tap into a proper fuse and for extra protection I'd add in-line fuse for the fog light. If you want to get more expert advice
log into 'www. the12volt.com' and register, then you can raise your specific question. Folks there are very friendly and many guys are MECPs.
That's where I learned how to install remote starter for my '15 RX Hybrid.

808newbie

what 2URGSE is saying is that if you want to do an add-a-circuit for the fogs you can use whichever fuse is adequate for your needs. but probably for what your doing you will be adding a switch to have independent control of your fogs (which will be in the cabin) so either way you will still need to route wires to the cabin. (im thinking you would want to have fogs turn on without headlights as well

DrRMHISF

Ok. I think there is some confusion.

The OSRAM kit needs a perm live, a perm GND and a switched live (plus a hard plugged connection to the existing fog wiring).

The live and GND are easy, the plugged fog is easy, there's a fly lead to determine the DRL intensity which is easy as it goes to the GND for 100% intensity. The independent control of the fogs comes from the connection to the existing fog cabling. What I'm missing is the switched live to trigger the DRL. I'm expecting the control box to do the rest.

Maybe my understanding / terminology is off. I have fuse tapping unit that takes the place of an existing fuse and adds a second fuse which I'll attach the trigger wire to. Is that not an add-a-circuit?

So I just need a switched live fuse in the engine bay.

2URGSE

Correct. You pull the original fuse out and plug it into the module, then you add another fuse with whatever value you need for the new device. When I hard-wire radar detectors, I usually add a 3 amp fuse (example only, contact the maker of the fog lights to see which fuse value you need). Make sure you disconnect the battery before you start.

As for whatever controls the on/off, if it's an existing switch in the interior, then yes, you can go via the fuse box in the engine bay with the add-a-circuit.

DrRMHISF

OK, got it.

However, I'm after a feed that is switched live, not the permanent live that will come off the battery itself. Simple question; which fuses (if anyone knows off the top of their head) in the engine bay are switched live?