Lighting upgrade project questions.

[arco777]

Long story with only one picture - but any input is appreciated!

My 94's headlights will cut out after about 20 min of driving and I can feel the switch getting hot. I assume the switch is just growing old, as it is getting slowly worse over time. High beams behave the same though, which is weird because I don't think their current runs through the headlamp switch, rather it runs through the dimmer/flash-to-pass switch. Either way, low and high act fine with only one headlight connected; I take this to mean that my old headlamp wiring is just not sufficient to run the lamps for long. I don't trust it to handle the addition of auxiliary lights any better.

I decided I'd wire in a couple relays; two, so I retain hi/low and flash-to-pass functionality, and since they're 40A relays they'll also handle a pair of 55W auxiliaries I will soon be installing with a Limited bumper. I want the aux lights to be always on with both the low and high headlamp beams, so I don't have to have another switch in the dash. I have 10A inline fuses for the headlamp high and low beam circuits (2x55W bulbs=9.2A), and when the fogs are installed they will get a pair of 10A fuses (plus homemade lexan rock shields).

The new wiring setup will pull both pos and neg straight from the battery connectors, just personal preference to go that route. All wiring will be 10 or 12 gauge depending. It should leave all stock wiring intact should I choose to revert, take the load off the switches since they'll only be operating the relays, add fuses for safety, and be easily expandable.

I am using new high-temp bulb connectors and going from 9004XVs on 12.8V to 9007XVs on 14.4V (running voltage). I don't mind the consequent 75% decrease in lifespan; I figure I should still get at least 90 hours out of each pair of bulbs which is fine with me. With 9004 to 9007 netting a 30% light increase, and an additional 50% output from the overvoltage, plus a couple 55W aux lights on the bumper, this thing should light up the night for cheap. I bought a 3M lens resurfacing kit too.

A wiring diagram I drew up is attached - I have all the parts (except aux lights), just need to start putting them together. Any input is welcome or if you see anything I did wrong please let me know. If nobody says it won't work, I'll start assembly tomorrow :

 

[Anime]

Ford's poor switch design on these eventually wears out (or catches fire and incinerates the vehicle), so a replacement usually fixes the issue.

That said, running the headlamps off relays is a common upgrade and will give a vast improvement over the stock routing and dinky wiring.

I'd urge you NOT to use 9007 bulbs in the stock '94 headlamps. Though they can be modified to fit the 9004 opening, a 9007 bulb has a very different filament arrangement, and combined with the reflector and lens made for the bulb/filament of a 9004, you could wind up putting light straight into the eyes of drivers of oncoming cars and cause an accident or worse.

Using the 9004 XtraVision bulbs with relays should give you quite an increase in light output, especially with newly cleaned lenses. There shouldn't be any drastic reduction in lifespan, or anything even close to 75%, since a 12-14.4 voltage range is perfectly normal.


Based on the diagram, the only thing I'd say is be sure to wire up the fog lights the same as the headlights, and use a seperate relay for them, don't try to run a set of fogs off the same relays that are being used for the high/low headlights. Basically use one relay for each pair of filaments. One for low beams, one for high beams, one for fog lights, etc.

 

[hazmat456]

you can not run the fogs off of both relays, you will backfeed the second relay, I agree with Anime get a third relay. I would wire that third fog light relay into the parking lights so the fogs are only on with them I would also recommend a forth with a switch so you can shut them down independently, for four dollars a relay it is alot easier to do it now.

 

[arco777]

Thanks for the input guys. I was planning to aim the 9007-equipped lenses down after install, they need adjustment anyways. As for the 75% for 50% thing, I was going off this - http://www.explorerforum.com/forums/showthread.php?t=181879

I wasn't too sure about the fogs on the same circuit as the headlamps, dunno what backfeeding is or what the effects are. Don't the relays have diodes in them already? I could add some.

I guess it wouldn't be too much work to add a couple more relays for the fogs but I figured 40A should handle the current of lamps plus fogs without any trouble.

Then again, wiring the fogs to be activated by the parking lamps wouldn't be too bad, pretty easy I guess... it's not really what I wanted though

 

[Bill Kemp]

Fogs would be best if on a seperate relay activated by the parking lights. They would be on any time the headlights hi/low are on. Isnt that what you want?

I assume your also changing the headlight switch.

 

[arco777]

I'd kind of like to be able to just have the parking lights on by themself, but I can deal with them being on with the fogs. Probably what's going to end up happening.

I don't plan to replace the switch because it should be fine if it's only running relays, and last time I tried replacing it with a junkyard switch it was a pain in the butt and ultimately the wrong switch.

 

[Anime]

You should replace the switch for safety reasons if not just functional. When the switches start going bad, they can start a fire. NOT what you want. The $10-30 for a new one isn't worth losing the entire vehicle. Get a new switch on ebay if you want it to be inexpensive, and pull yours to match it up so you know it'll be the right one.

The fogs won't come on just by turning on the parking lights. When you use the relay to the fogs, it just uses the parking lights (rather than low beam) on the relay terminal to allow the fogs to be on. In a traditional fog light install, the relay is wired into the low beams so the fog lights can only stay on with low beams, and when the high beams are on, or the low beams are off, the fog lights won't turn on. This is actually a legally required method of installing aftermarket fog lights in some states, due to some laws about having to have headlights on with fog lights, or not using fog lights as primary lighting. Of course, that defeats the funtion of TRUE fog lights, which are quite effective in fog without the headlights. The law makes sense for most people running cheap fog lights, which definitely wouldn't give enough visibility to drive more than 10-20mph.

A 40A relay probably could handle two headlights and two fog lights, BUT they'd all HAVE to either be on or off. Each seperate relay makes for a stand-alone lighting system, which is what you want so you can have the fog lights on or off independent of the high or low beams.

 

[arco777]

Good information but I'd really like the fogs to be on during both high and low beams, without separate control of them... there are times I want to illuminate an area when I'm working in front of the vehicle and high beams plus fogs would be ideal. Using the parking lamps to turn on the fog relay is fine with me. I wouldn't drive with the just the fogs on that way either, because I am pretty sure it's illegal to drive with parking lamps on and headlamps off.

I will check the parts stores and see if they can get me a new light switch, if so I'll buy it and a couple more relays. Thanks!

 

[Bill Kemp]

I have driven from Mi to Fl, Mi to NY, Mi to VA, Mi to IN, Mi to MO all with parking lights & fogs on only. Not when headlights should be on due to darkness of course, and have never had a problem. What the hell, just call them DRL instead of fogs. Whats the diff.? Just use the pkng lgt wire to activate a 30A relay for the fogs if you dont want to use a seperate switch.

 

[Anime]

If you want the fogs on when the highs and lows are on, just leave the switch on.

If you wire the switch to be the high/low beams the fog lights will never go off. You'll be going through bulbs fairly quickly. It also annoys people when you have your fog lamps on and they glare in their eyes but theres no fog or foul weather.