I have been around town to four different truck shops with this same question:

I want to have IPF Driving Lights on a Bull Bar, and have a master "on/off" switch - and then have the high-beams trigger the relay to turn on the IPF lights when the master switch is "on."

Truck shops 1, 2 and 3 told me that this would be no problem at all, and were happy to do it for us that way.

Truck shop 4, which is the one that I liked the best, advised us that he would do it if we really insisted, but that he is hesitant to do it in case there is an issue with the lights at some point that then sends feedback back up the circuit and fries the OEM electronics, and would thus become an issue with our warranty. His suggestion was to have the Dodge dealership wire it into the high-beams for us, which would likely cost an arm and a leg. His suggestion was to just wire it in as a separate system with its own independent switch.

I really dont want to be flipping switches AND turning off high beams every time we have oncoming traffic on a road trip. I would really like them to come on with high beams. I cannot think of why it would fry the factory circuitry if it was installed correctly - is there something I'm missing? I could go with any of the other 3 shops who would do it for me - but I don't want something to go wrong and then have them tell me "well that's not our problem."

What would you suggest?

As an aside: I am trying to think of a nice place to mount the on/off switch for the lights. Does anyone have pictures of where their light switch(es) are mounted? And how were yours wired in?

Thanks!

 

The only thing i can think of that could cause an issue is that the lighting on the current gen vehicles is not like it was in years past, that is in much the same way that the accelerator on a modern car is often not connected to the throttle, the headlight switch is not connected to the headlights, but rather to the vehicle's bus (at least for the fogs, not sure about hi beams)

That said, I am thinking it will be a non issue. I would just tap into one of the headlights for a relay, run power to it from your master switch (which also should have a relay, but hey, I am ****) wire the lights in parallel to each other and ground them out, you should be fine.

 

You could do this:

Highbeam Circuit -> 'master switch' -> NPN transistor

The transistor would then switch the coil of the relay.

You also wouldn't have to worry with an additional relay on the 'master switch' circuit as it would carry almost no current. Reference this link http://www.technologystudent.com/elec1/transis1.htm and replace the LED with the coil of the relay.

A normal 30 A relay coil draws about 200 mA. I don't know how sensitive the truck's bus is, but the transistor would only draw a few nanoamps if you size the resistors correctly.

 

check this out
http://www.cumminsforum.com/forum/3r...g-out-ecm.html

 

Most likely, the people who "fried" their computers were those not using a diode to properly shunt the reverse voltage generated by the collapsing magnetic field in the relay.

I still say that a NPN transistor fed from the high beams are the way to go. It is basically the equivalent of connecting your volt meter to the high beam wire. It is just a device that detects voltage, it is not using the high beam circuit to do any work like the relay would.

People seem to like to see a circuit... So here is one I drew up. Using this scheme, the headlight circuit would see an additional 12 mA of load.

 

True. most people who have had problems is because it was wired incorrectly. I just wanted to post it as a warning.

Look into the fogzilla, or fogster. from BriteBox. They might have something that will work for you.
http://www.genosgarage.com/products.asp?dept=9