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Increasing headlight output using parallel MFS ground wiring

5K views 11 replies 3 participants last post by  noluck4 
#1 · (Edited)
I found a couple of mentions from chartmaker that headlight output can be improved (at the cost of bulb life) by adding parallel wiring from the MFS to headlights.

Such a solution would be great for me because I use the headlights very little. I also have a bunch of replacement bulbs that I got for next to nothing thanks to closeouts and rebates at Rockauto.

So I have some questions for anybody who has done this:

1) Is it reasonably easy to route the new wire(s)? How much wire will I need?

2) Is it just the one wire from the MFS to the left headlamp? Or do I need to run another wire to the right headlamp to maintain voltage to that side?

3) Since I use the headlights so little and have enough spare bulbs, is it worth getting more than a 12 gauge wire here? Also, I haven't done the "big 3" so does that make any difference?

I've added in chart's diagrams and info from previous threads.




 
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#2 · (Edited)
I looked at the routing of the wire from the MFS to the HL and it looked like a lot of work. Pic my relay diagram and pic of the harness built out of the car ready to install. Wire on a bench/driveway is much easier than in the car. Need a relay and fuse/holder. There is a differnece between the diagram and the actual harness. I ran a new connector from the two headlights. Thus I keep all the OEM wires intact so the system is easier to do out of the car. The inbetween the lights jumper wire needs to be opened to do the install and then reconnected. Otherwise it is plug and play. Power from the battery + for the relay, using a low amp fuse and a good ground wire to the battery cable. This is for low beams only, same can be done for high beam with a second relay.
I do not cut any factory wires on the vehicle, only on the HL assembly.
I have been using this for 4 years but use XTravision Sylvania bulbs which have higher output and better life at the same time, but not much.

-chart-
 
#3 ·
#4 ·
#6 ·
Just received the Nokya harness. Will be installing soon.

Doing some comparing / research, I believe these are identical to Putco's harness which would mean Putco's wires are 14 gauge as well. The only difference seems to be black insulation (Nokya) vs yellow (Putco).

I've seen comments that Putco's harness does not come with a fuse. While this appears to be the case, and also the same with Nokya, all is not as it appears. The two positive wires are actually 16AWG fusable wire links. This does the work of a fuse and is why there is a connector in the middle of the positive wires - it connects the 16AWG fusable positive wires to the 14AWG regular positive wires.

I've been able to remove the pins from the bulb holders and it looks like the pins in Ford's bulb holders can also be removed. Hopefully the holes are big enough to squeeze the pins through, so I hope to be able to do a plug and play install. The downside is that Putco's relays have a reputation for being unreliable and it appears the Nokya relays are the same product. If they fail with what little light usage they will see, I'll change them out entirely for a reliable brand.

On balance, either a home made harness or the harness on ebay with better relays but 16 AWG might have been a better choice.

14 or even 12 or 10 AWG isn't as important as I thought after I ran the numbers (the stock Taurus baseline is truly bad). Even using 16 AWG over a total distance of 10 feet for the passenger headlight only drops 0.3 volts, which would still deliver on average 13.7 volts. An 11 AWG harness would deliver 13.9 volts which in light output terms is not that different. 16 AWG also gives longer bulb life.
 
#7 · (Edited)
#8 ·
If its your 2004, and using a better harness, I made a thing for this a while back you might find interesting. http://www.taurusclub.com/forum/117...65-my-rough-draft-how-heavy-duty-harness.html

I am happy to report everything still works excellently. It paid for itself the last few winters when I would take the bull instead of my new car when it was expected to be REALLY crappy out.
Every one to their own plan.
But see pic, this requires only a simple relay, fuse holder and 2 wires to hook to ground and battery +. No cutting anything but wires. Transfer from one car to another, disable easily. Wire work done off the car. My lamp enclosure is not opened up to the dirt/water of the elements.

Pic was when I moved this from '01 which I sold to the '03 which I bought.
Cars keep their own enclosures, only modifications done on the wires to the bulb holder/weather cap.
Just my take.

-chart-
 

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#9 ·
Thanks noluck4.

Although I used the same harness kit as you, I ended up doing something a little different. Like chart, I didn't want to alter the lamp enclosure. And since I have a stock of posi-twist connectors, splicing is reliable and relatively easier as well.

So I removed the existing wiring and sockets and installed the new wiring and sockets all the way into the enclosure. Just felt it would be a pity not to use the 14AWG wiring all the way and to not use the sockets that came with the harness kit.
 
#11 ·
Depending on the kit, Putco changes the system from ground switched to power switched, which has no good advantages. Cut wires and use existing enclosure seals makes sense. I am old school and use solder and shrink tube. The OE wire from the left to right lamp means a slight loss and the right lamp will be less bright but it is so minor, it only means the left will burn out first. And when the left burns out, the right has more volts and will accelerate it's fail. Possible both bulbs burn out if they are equal age.

Ground switched HL are safer and require less wire runs. Short in the wire from inside to outside results in HL "on" as opposed to pos switched resulting in HL "off". I have had total HL fail at night, sudden without warning. That will get your attention. :angry:

-chart-
 
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