This is for my '98 Expy. I have an aftermarket HID system on the truck running the low beams only (an older system) that works very well. Recently I put a grill gaurd on the front with some PIAA off road lights. I wired those lights in to the high beam switch since it wasn't being used.

Problem is that when I turn just those on I loose all the peripherial light b/c the low beams (HIDs and fog lights) go out. I would like to wire it up so that there is a one-way relay so that when the high beams are turned on it automatically leaves the HIDs on as well. (I can find a post on how to keep the fogs on with the high beams as well if I want later).

Here's where it gets tricky. To activate the high beams you PUSH the lever forward. This turns off the low beams and leave the high beams on. However, when you PULL the lever towards you it "flahshes" the high beams and you must hold them on. This does NOT turn off the low beams (and therefore provides exactly the type of lighting I would like to have). I'm concerned that if I wire the high beams to activate the low beams that there might be a problem trying to send power to the low beams if they're already lighted. Will it just be a 2nd source of power for them, or will I burn a fuse (or worse) by sending power to them twice?

Thanks for your help.
-Scott

 

A lot of 97-98 F150s (not too sure about expy) had/have the wiring in place for fog lights even if unequipped. The headlight switch even has the fog setting. I'd wire the offroad lights to the fog harness (if its there), and call it a day.

Factory Fogs

Went back to find a thread that gave more info than I did. Seems a lot of folks over-think this kind of mod. Look for the "white caps" on a wiring harness that ends were fog lights would have been. BTW: To see if you have a fog equipped highlight switch, it PULLS OUT when the lights are on.

 

Thanks for the reply.

I have fogs on my truck. And actually - everything works just fine now when I pull back on the brights to make the off-road lights work with the low beam and fogs. I don't want the off-road lights on all the time thought.

I just want to make sure that there won't be any problems if I wire the lights such that the low beam lights would have two sources of power that could both be on at the same time.

ie: They COULD be on as normal, but they could also, at the same time, recieve power from the high beam switch. Would it just ignore the second input of power or will it fry my truck?

 

HMMMMM.

There are a lot of factors here. You probably can run all the lights at the same time if the flash-to-pass energizes everything without blowing a fuse. The thing I'd be worried about is damaging the wiring or lamp housing. If you do a SEARCH on melted harness you'll probably find a few threads. I remember a rash of posts from guys that had installed aftermarket lamps (hid, cool white, whatever) that melted either their headlight housing, lenses, harness, or all of the above.

This may be one of those jobs that may not be worth it.

 

OK - Now you've got me 2nd guessing the whole thing. You're right and I hadn't thought about this at all.

The HIDs are only 35 watts, so I'm sure that's not it. But I don't know what the normal stock lighting normally draws. The off-road lights are 85 watt and I would hate to draw more through the line than it can handle. I'm very glad that you brought this up.

I think I'll just wire the fogs up so that they turn on with the brights (off-road) and hope that it fills the gap for me. They're low enough current that I would think it'll be OK.

The reality is that I rarely use the high beams to begin with. I think you may have just convinced me that I'm making more fuss than I should be over something I will rarely use.

Thanks!