Question about upgrading wire harness

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Originally Posted By: Ken2
Originally Posted By: MisterBen
I measured my 2009 Tacoma, without the engine running. I was getting about .45v drop on the driver's headlight, and about .75-.8v drop on the passenger.

I've been pondering making a harness because of that.
Toyotas (as least mine) switch the negative wire, not the positive, for the headlights. That makes designing the wiring harness more challenging. I did it, but didn't keep a diagram.


My car is not like that. I know that many (if not all) Toyotas are like yours is.
 
I've been through the wiring diagram, and it's not negatively switched. Well, it IS, but it's negatively switched inside the cab. The bulbs themselves are positively switched through the relay.

I've been through the wiring diagrams. I also had auxiliary lights switched through my hi beams, and they worked fine.
 
Originally Posted By: MisterBen
I've been through the wiring diagram, and it's not negatively switched. Well, it IS, but it's negatively switched inside the cab. The bulbs themselves are positively switched through the relay.

I've been through the wiring diagrams. I also had auxiliary lights switched through my hi beams, and they worked fine.


Ah, I realize now that you have a Toyota truck. I have read on a lot of Tacoma forums about upgraded harnesses and none of them seem to have issues with the negative switching like the Toyota passenger cars have.
 
My only concern is I've heard the computer puts out an error code for a burnt out headlight bulb. I think it has to actually have something in the circuit though, and I just can't see it!

Good to know you've read others that have had success.
 
UPDATE: I received my suvlights harness in the mail yesterday. I was very impressed with how well-constructed it was. It was very neat and clean; almost looked OEM, except the wires were incredibly thick (very much unlike OEM
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) I just installed it, and although I wasn't able to notice a difference, since it is midday, everything does work correctly. I'll report back tomorrow after I take it for a drive tonight. I must say, the customer service is not good... that's when you're actually able to contact someone. Otherwise, it's nonexistent. I called and had to ask about my order, after which it shipped the next day. But I will say, they do make a hefty harness though!
 
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I have still yet to drive on the country backroads around here, but overall I can say that the harness is making a slight difference so far. The light output is definitely slightly whiter. But most of my driving has taken place either in the rain, or under streetlights, so judging increased light output is difficult. The only complaint I have is that since the actual connectors to the bulb have a thicker & longer base, the "retaining ring" used on 9007 bulbs will not fit through this ring, and from what I can visually discern, also will not secure it, since it is longer than the factory plug (does that make sense)? It isn't too much of a problem, since I am still making use of the circular dust shields that snap on behind the plug, and they are doing a pretty decent job of holding the plugs in place, snug. One of these nights this week, I'll be driving to the in-laws, which requires going through some dark, twisty, hilly roads. I'll report back!
Overall, I'll have to say that the 9007 bulb/housing combo is very poor, at best. And should never be used again
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Poor light output, poor bulb design, stupid snap rings and dust shields... Lose lose lose in my book. Nice harness, though.
 
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I agree that there are better bulbs than the HB5, but the Focus' headlamp's optics may not be that great either, making a particularly poor impression. The light output from either of my Dodges that used this bulb ('97 Dakota and '03 Grand Caravan) was pretty good. The Dakota didn't have a nice upper cut-off like the van did, but light spread within the beam was good and intensity was pretty good as well. It's passable today, and was certainly respectable for 1997.

I do hate those silly retaining rings. I am surprised that the Focus was still using the HB5 in 2007. Ford was generally an early adopter of the newer H13 bulb.

Compared with a modern projector setup with H11s such as on your Fusion, yeah, an HB5 multi-reflector setup like on your Focus will disappoint every time. After you drive with a harness and upgraded bulbs for a while, you'll find it hard to imagine people drive with STOCK bulbs at night anymore. Ha ha.
 
I remember my '04 Neon had the 9007's, with pretty respectable output. My Focus actually has a decent cutoff, and isn't too bad for a 9007 (I've owned 3 cars with 9007 bulbs), but my last car, which I sold in January, had a 9006/9005 setup. And even for a 1997 car, it produced good, useable light (especially when you stuff a 9005 bulb into a 9006 socket
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) Hokiefyd, do you have an upgraded harness also?
 
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By the way, the comment I made a few days ago about the retaining ring for the 9007 bulb not fitting after I installed the harness... Forgive me, I had a dumb moment
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I realized that the ring holds on only the bulb, and has nothing to do with the plug from the harness being thicker. So today I unplugged the harness from the bulb, put the retaining ring on each side, and plugged the harness back into the bulbs. Problem solved! I had noticed that even though the rubber dust shield pressed against the back of the bulbs and held them in place, the bulbs still moved around a tiny bit, which makes a BIG difference in beam and light output. One of my retaining rings looks warped/broken, and doesn't do a very good job of holding the bulb tight, so I'll replace it sometime soon.
 
Yes. Definitely a little brighter/whiter. The beam also seems to be able to reach a little farther as well. Overall, it works well. I'd recommend it. I think that a harness works even better for people who have older cars, since the wiring usually corrodes more over time. My car is only 4.5 years old.
 
Good deal. I am toying with the idea of a harness for the Cruze. It's not quite lighting the road like I'd like it to.
 
Originally Posted By: Klutch9
Yes. Definitely a little brighter/whiter. The beam also seems to be able to reach a little farther as well. Overall, it works well. I'd recommend it. I think that a harness works even better for people who have older cars, since the wiring usually corrodes more over time. My car is only 4.5 years old.


Glad it worked out for you. My F-150 is a bit aged, and I plan on doing a relay for it one of these days. I have no complaints about the lighting using the Xtravisions, but still, I have to have something to do, I suppose.
 
Bumping this...

I'm considering rolling my own harness. The only harnesses I found for a H13/9008 bulb were either the cheesy Putco harness or HID harnesses with 9006 connectors. It's expensive to DIY! Right now it's looking like a DIY H13 harness will run about $80 after the parts and solder are included. That's using 10-gauge wire, Tyco/Bosch relays, and H13 connectors I'd need to pin myself.

10-gauge is overkill, but I like overkill when it comes to headlights! And, buying 10-gauge wire online is the same as buying 14-gauge locally.

Thoughts?
 
Use GXL insulated wire, not GPT (which is what most of what you'll find for sale). The GPT wire does not hold up to underhood temperatures and the insulation will become brittle and start cracking.
 
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