New wiring harness improves light output

Status
Not open for further replies.
B

bprimerano

Joined
Feb 21, 2008
Messages
43
Location
NY
I have a 99 Saturn SL2. I wanted to try to build a new wiring harness that would deliver more power to the headlights. I used MOSFET power transistors rather than relays that are normally used. I have not installed it yet, so I can't comment on reliability, but I did try it long enough to get some voltage readings.

Low beams
Stock 11.94 volts 47.8 watts 788 Lumens
New 13.95 volts 65.3 watts 1340 Lumens

High beams
Stock 11.76 volts 54.8 watts 1275 Lumens
New 13.60 volts 73.5 watts 2095 Lumens

Add to this the fact that the low beams stay on with the high, and visibility is greatly improved.
 
Awesome upgrade. Just make sure the fuses can take all the power and don't blow out.

Is the new wiring harness fed straight off the battery for power?
 
You a getting more light then the guy that just plugs in some bulbs with twice the stock rating
11.gif


That's one of the best ways to improve a cars lighting, although I don't see any real world advantage to a MOSFET over an electromechanical relay.

One potential problem is the extra heat you are putting into your lights by running low an high beams together. Unless high and low beams are different bulbs and it doesn't make the headlight unit run hot, it's not a good idea to run both at once for long periods of time.
 
Originally Posted By: Spartuss
Awesome upgrade. Just make sure the fuses can take all the power and don't blow out.

Is the new wiring harness fed straight off the battery for power?


The new wiring ties in at the end of the battery cable where it powers the relay junction box. Two fuses are used near the connection point. One fuse for each side, like the factory set-up. I have 20 amp fuses in.
 
Originally Posted By: XS650
You a getting more light then the guy that just plugs in some bulbs with twice the stock rating
11.gif


That's one of the best ways to improve a cars lighting, although I don't see any real world advantage to a MOSFET over an electromechanical relay.

One potential problem is the extra heat you are putting into your lights by running low an high beams together. Unless high and low beams are different bulbs and it doesn't make the headlight unit run hot, it's not a good idea to run both at once for long periods of time.


I tried relays. I like the MOSFETs for their smaller size and cheaper price. Reliability could go either way.

The high and low beams are separate 9005 and 9006 size bulbs. This is a common mod on a Saturn. Your right, I would not do this with dual filament bulbs. I drive a lot of country roads with LOTS of deer, so this does really help.
 
Last edited:
This is an awesome mod. My friends '97 Saturn SL2's low beams do come off when the high beams are on. I wonder why Saturn did this. On many cars that use different bulbs for high and low beam lights, have the low beams stay on, when the high beams are activated.
 
A problem with running high and lows together is that the eye tends to focus on the lit area. Running only highs gets the eyes to automatically look into that lit area, and we want to be watching far ahead as possible.

You might also upgrade your bulbs. The 9011 is a great upgrade for the 9005. Ditto the 9012 for the 9006.
 
Originally Posted By: Spartuss
This is an awesome mod. My friends '97 Saturn SL2's low beams do come off when the high beams are on. I wonder why Saturn did this. On many cars that use different bulbs for high and low beam lights, have the low beams stay on, when the high beams are activated.

it's not a saturn thing, it's a federal thing. every car I've ever owned is set up to turn off the lows when the highs are engaged. I would be interested to seewhat cars you are referring to that do not do this.
related also, on my MPV w/ factory fog lights, if you engage the high beams while the fogs are on, the fogs will turn off.
 
Originally Posted By: mpvue
Originally Posted By: Spartuss
This is an awesome mod. My friends '97 Saturn SL2's low beams do come off when the high beams are on. I wonder why Saturn did this. On many cars that use different bulbs for high and low beam lights, have the low beams stay on, when the high beams are activated.

it's not a saturn thing, it's a federal thing. every car I've ever owned is set up to turn off the lows when the highs are engaged. I would be interested to seewhat cars you are referring to that do not do this.
related also, on my MPV w/ factory fog lights, if you engage the high beams while the fogs are on, the fogs will turn off.


I would be surprised if this is right. Many name brand stores carry harnesses that do exactly this. I know my 79 Corvette has 4 high beams at one time. I don't see why I can not have 2 high and 2 low.
 
Originally Posted By: Ken2

You might also upgrade your bulbs. The 9011 is a great upgrade for the 9005. Ditto the 9012 for the 9006.


I've seen these. They look good. I'm not sure I want to pay $120.
 
USDOT has a limit on how much wattage can be "on" at one time with headlights and foglights. that is why you don't have high and low or high and fog on at the same time.
 
To the OP: can you please tell us where you got your parts from? I'd love to do this to my Buick with the 9005/9006 headlights as well. Thanks!
 
Originally Posted By: mpvue
Originally Posted By: Spartuss
This is an awesome mod. My friends '97 Saturn SL2's low beams do come off when the high beams are on. I wonder why Saturn did this. On many cars that use different bulbs for high and low beam lights, have the low beams stay on, when the high beams are activated.

it's not a saturn thing, it's a federal thing. every car I've ever owned is set up to turn off the lows when the highs are engaged. I would be interested to seewhat cars you are referring to that do not do this.
related also, on my MPV w/ factory fog lights, if you engage the high beams while the fogs are on, the fogs will turn off.


there are many cars out there whose low beams do not turn off when high beams are on, but I will list the ones I've owned or family members have owned that do this:

'97 Toyota Avalon
'01 Acura 3.2TL
'04 Infiniti G35
'98 Acura Integra GS-R
'04 Nissan Altima 3.5 SE
'06 Honda Pilot

and many more...
 
Last edited:
Originally Posted By: sciphi
To the OP: can you please tell us where you got your parts from? I'd love to do this to my Buick with the 9005/9006 headlights as well. Thanks!


Check out this web site.
http://www.suvlights.com/index.php?cPath=24_74

This is another good one.
http://www.danielsternlighting.com/products/products.html

I ordered the MOSFETs from Digi-Key. If you go this way, you'll need to know whether your headlights are switched on the high side or the low side. You'll need to build them on a circuit board.

Building the circuit board from prototyping board is a little time consuming. If there was enough interest, I am thinking about having some circuit boards made up.
 
Originally Posted By: bprimerano

Low beams
Stock 11.94 volts 47.8 watts 788 Lumens
New 13.95 volts 65.3 watts 1340 Lumens

High beams
Stock 11.76 volts 54.8 watts 1275 Lumens
New 13.60 volts 73.5 watts 2095 Lumens

Clever.

And I can see this sort of mod being potentially useful on a car that doesn't have very bright bulbs available for it. However, this mod is not without "hidden costs", beyond the initial mod cost. Specifically, over-driving your lights (like you are intentionally doing) will use a little more electricity (which will lower you fuel economy some, due to higher alternator drag on the engine), will produce a little more heat (which potentially could cause some issues in the headlight assembly), and will cause your bulbs to burn out quicker (which means you will be replacing them more often). So while I could see the value of this mod, you also have to factor in the "hidden costs" of the mod as well.

However, since (in a different post) you mentioned your car uses 9005/9006 bulbs (as does my CRX, btw), why didn't you just leave the stock harness and switch to Toshiba HIR bulbs (which will easily fit in a stock 9005/9006 socket with only minor modifications to the bulb tabs)?
https://bobistheoilguy.com/forums/threads/toshiba-hir-lights.61028/

Not only will a HIR bulb upgrade give you even more light than your wiring mod is giving you, but they also retain stock power and heat usage, and close to stock bulb lifetime ratings. So with the HIR upgrade (which I did on my CRX, btw), you get even more light than your mod gives you, without any of the "over driving the bulbs" downsides your mod gives. In fact, about the only down-side I've found to the HIR mod (other than the cost of the bulbs), is that it really only works on those cars that use 9005/9006 bulbs (whereas your mod could potentially work on just about any car bulb, not just cars that take 9005/9006 bulbs).
 
He's not over driving his bulbs, he's no longer under driving them. The bulbs were designed to run on standard vehicle voltage in a vehicle with good wiring. Bulb life will be shorter than it was Saturn stock but he will get still design bulb life, which is not bad.

The HIRs with stock wiring would put out less light than his stock bulbs with good wiring.
 
Let me say that this is not new. Many sites sell harnesses that do this. There is another thread below this one where they are talking about this same modification. What is new is using the MOSFETs instead of relays are driving the low beams with the high beams. Again, this is a common mod but this is the first time a harness has been made to do both, as far as I know.

I think you are right, both changes would result in similar amounts of light. I think the HIR bulbs will cost more in the long run (unless my lifetimes are severly impacted) with the advantage of using less power. You also do not get the advantage of having lows and highs on together with the HIR bulbs(at least on my Saturn I don't).
 
Did you keep the DRLs or cut them out when you did the mod?

I was confused by the 80's style quad headlights until I got a cadillac cimarron with them. The outer bulbs have two filaments while the inners are highbeam only. So the outer bulbs switch from low to high. (Had both low beams burn out at once and was confused.) Vertical glass lenses let the light go straight through, not diagonally like the modern aero stuff, and they never yellowed or faded. I had halogen bulbs of course. Pretty good forward lighting on high.

A modern equivalent would be 9004s on the outside and 9006s in the middle.
 
Originally Posted By: eljefino
Did you keep the DRLs or cut them out when you did the mod?


I had removed the DRLs prior to this mod. This mod would also automatically eliminate them. It would be tricky doing something like this and keeping the DRLs.
 
Status
Not open for further replies.
Back
Top Bottom