I'm trying to install some driving lights in my 2004 f150. I want them to come on when I turn my brights on. I plan on using the relay for the brights to control another relay. I have located the relay for the brights, but I see no way of tapping the relay. Do I need to get a multimeter out and test each wire going into fuse/relay box? Or is there a easier way?

thanks

 

Not going to be much help but....Your either going to need to get out the multimeter and look for a lead that only gets power when the highs are on or just splice into the wire that goes to the high beams and pull power for the relay there. Ive spliced into the headlight before did a little soldering and some heat shrink and it was good to go. Just a thought since no one has replied...

 

Don't kick me to hard about this but you do know it is not legal to run lighted driving lights with high beams.
On all factory setups, on all the cars and truck iv'e saw, the driving light are not permitted on with high beams by design.
I know many ignor it.
If you do this, be good about checking the aim so oncoming drivers are not blinded.

 

Thanks for the heads up. I just can't imagine a reason I would be driving with high beams in traffic. I had the same setup in my last truck and I loved it, so I'm trying to emulate my last setup.

I actually went out and got one of those add-a-circuit kits that piggyback onto fuses. I thought it would just be easier than using a multimeter all day.

I got everything working, except for one little problem. I also hooked a switch into the lights so I could have them on without highbeams. The problem is that when I hit the switch my highs go on because the voltage is traveling back through the circuit. A diode will fix it, but I'm not a fan of extra work right now.

 

Having them come on with the high beams is an easy thing to do.
Use a 30 amp relay with one side connected to the high beam lead, the other side to ground. This will operate the relay with the highs.
Then supply 12 volts through a fuse to one contact of the relay then on to the running lights from the other.
Only problem is you have no other control of those lights except by going to low beam to shut them off or installing another switch seperate, in the circuit.
Can be done a number of ways depending on how much control you want.
I have my car's high and lows fully controlled by relays with seperate fused feeds to get the high current flow through the headlite switch down to only that of the small currents the relays consume.

 

You said that you hooked a switch as well. Thought this post from awhile back might come in handy as I think it will get rid of the need for a diode. Could probably just replace the switch and be done with it. Hope it helps...


https://www.f150online.com/forums/sh...hreadid=166781

 

Good Info.
Thanks

 

hmmm I read through the thread, and I'm not sure its a better idea than a diode. (at least in my situation)
I drew up a diagram (to the best of my ability )of how I basically have everything wired up.


Notice the switch is not connected to the battery. I spliced the switch's 12V input from the 12V constant line I use for my stereo's head unit. I figured I would only need < .01 amps to trigger the relay, so the head unit wouldn't complain.

If you look what happens after I trigger the switch, the voltage will go both to the fuse box (highbeam fuse) and to the relay. Which means I am running the relay and my high beams off 22 gauge wire.

I would like your opinion on this, but I feel since the switch's existing wiring is not setup to run any lights at all, I feel the diode would be my best bet. Otherwise I'm looking at about half a day's work to pull the wires.

If you think the diode is my best bet, is there any type I should use?

thanks

 

Why do the manufacturers do that? I mean, does it really matter if you have fog lights on with the brights? are the brights so you can see more? more lights = better able to see

I just don't understand....

 

In dense fog, brights will reflect off the fog and will actually make it harder to see.

 

Adding the diode would work. However, the only diodes I have personally seen are kind of like resistors and have one thick wire going in and out and it might be a little hard to put inline with braided wire. Just a thought. The reason I posted the other thread is that you would have the option of having the lights come on with highs, off completely, or on with the switch. I wouldnt think it would be that hard. You would just need to run the wire that is going from the fuse box to the switch instead of the relay. You already have constant power going to the switch and a wire going from the switch to the relay so adding the one wire would be it. Good luck!