switching hid spots with fog switch

On my 2005 Nissan Pathfinder, the switch for the fog lamps pull a single relay which in turn powers both fog lamps.

The Intelligent power circuit switches the 12v to that relay.

I want to turn on 2 HID spotlights mounted on the Brush guard with the FL switch.

My choices appears to be:

1) add another relay and switch both coils on the 12v rail from the Intelligent power circuit (parallel relay configuration)

or

2) Add a second relay, and let the SWITCHED 12v to the fog lamps also pwr the 2nd relay coil, which would in turn switch the HID voltage. (cascaded relay configuration)

Of course the HID lamps would be fused separately and have their own home runs to the main 12v rail.

I don't really see any harm in either configuration if using diodes with the coil.

By design, the fog lamps go off when I engage the high beams, but I wouldn't need the high beams and the HIDs at the same time anyway, so it's a moot point.

Thoughts or opinions?

TIA

.

If you can drive the second relay off of the same signal that drives the fog light relay that's what I would do.  You wouldn't need a diode in this configuration (and you wouldn't if you cascaded them either).

You would most likely add this relay under the hood so make sure you get a weatherproof relay.

Thanks again!

I guess my reasoning was that the fsm shows the ground being switched  by the IPM for this and I was leary about any inductive kick being on the main 12v rail, but if all the other relays don't cause a problem, I guess one more will not.

Roger on that weatherproof relay.

I finished my project today!

I flicked the switch repeatedly while hunting down the relay *requires assistance* and found the relay at the bottem of a stack under the hood sandwiched to the "Intelligent Power Module"

You are limited in disassembling this. The purple with 2 grey dots was the switched wire going to the FL relay, so I went with that.

I cut and soldered another power wire to it and used shrink tube. For reference sake, I will state here that all connections in this project are soldered with shrink tubing unless otherwise stated.

The new red wire was fed out and connected to one of the coil connections on a 30A relay.

The other coil contact went to ground with a spade lug.

The hot lead was switched through the relay to the + on the battery, and the other side fed straight to the lights.

I also ran ground leads to the lights and these are fused inline, with the fuse holders and the relay bound together with 2 black wire ties.

All of the wiring is loomed on black plastic that is not ran near heat. I ran the loom in front of the battery and out a small crack near the radiator in order to put some quick disconnects (the type used for trailers) near the hood release. The wires from my spotlights also have extensions soldered to quick disconnects and are loomed back through the black grille.

Besides having to make all the solder connections for extentions etc, I decided to replace the factory battery terminals *those crappy tin ones* with heavy lead ones. This was a considerable amount of work to do!

I had to take apart all of the + harness and connections and shim down with new post with a dremmel until it fit in to the plastic form. I cleaned and burnished all contact points.

The negative was another story. The main cable was grounded to a metel stand-off and then to the engine. This is a VERY CRAPPY was of doing things. I had to remove the cable, the stand-off and the engine bolt. I used the dremmel to burnish the connections on the copper lugs and where the stand-off was seated in the engine area. Then put it all back and add the new ground terminal and bolt all connections down solid. This was a lot more work than it seems in my desciption.

The end result is all new pwr connections and the ability to turn the FL switch in the cabin and turn on the HID spots. Works like a charm.

Photos forth coming.