Headlight Relay Harness Upgrade

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Notmikeb
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My tercel:: 85 Tercel 5dr FWD
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Headlight Relay Harness Upgrade

Post by Notmikeb »

One thing I've been wanting to do since day one is to make the headlights brighter. Between the sealed beam style and the 30 year old 20 ga wiring that was woefully inadequate even when the car was new, my headlights weren't inspiring a lot of confidence. I ordered a H6054 conversion housing set that mounts a standard halogen H4 (9003) bulb. They came with a stupid small blue bulb in the base of the light that I guess is supposed to tint the headlight beam. Pretty sure that is illegal anyway but I removed them and covered the hole with metallic tape to seal the housing from moisture. I also ditched the blue tinted headlight bulbs it came with and installed a more standard Sylvania bulb that I've used before on other vehicles and been pretty happy with.

The other thing I wanted to address was the voltage drop. I took a reading at the driver's side headlight the other day and was astounded to find only 10.8V..... WITH THE ENGINE RUNNING!!!! That is pretty unacceptable. Alternator seems to put out between 14.1 and 14.2 so there was a significant amount of loss in the wiring. I decided the best course of action was to re-wire the headlights directly to the battery via a relay system.

One thing that has to be taken into consideration when building this harness is that this car is a Negative-Switched system. I couldn't run the relays off just any ground, it had to be the headlight system's ground as that is where the switch is. This is what I came up with;
headlight wiring.jpg
(Pardon my lack of computer graphics skills. My schematic drawing skills are limited to MS Paint :lol:)

The only reason I made the high beam fuse a 20A instead of 15A was to easily be able to differentiate the two circuits in the future as most of the wiring is hidden in a taped up loom. I used 12 ga wire for the new circuit and 16 ga wire to adapt the original wiring into a signal circuit for the relays. Post install voltage at headlight is now 14.0v which I deem more than acceptable.

The end result was a much more modern performing headlight system that is easily twice as bright as the old one and makes me feel a lot better about driving around my neighborhood at night. We have tons of deer in our area and I never felt safe driving around at night with any sort of real speed. If I hit a deer with my Suburban, no problem! That'll buff right out! If I hit one with the Tercel..... not so much.
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1985 Tercel 5dr Hatchback
2003 Chevy Suburban
2014 Ford Flex

"I don't get it! I've cut this thing FIVE times now and it's STILL too SHORT!"
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ARCHINSTL
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Re: Headlight Relay Harness Upgrade

Post by ARCHINSTL »

Bravo!
I think the diagram is pretty clear, so no apologies are due.
I did something like this with my then-new '86 626 and was quite happy (its OE pattern just sucked). It did not use sealed beams.
I will have to check the voltage drop on Goldie.

Is there any downside to your system?
Thanks,
Tom M.
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Notmikeb
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My tercel:: 85 Tercel 5dr FWD
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Re: Headlight Relay Harness Upgrade

Post by Notmikeb »

The only potential issue I see in the future is that I didn't use new headlight plugs but individual spade terminals. The only headlight plugs I found at the local auto parts store had what appeared to be 18 ga wire and it seemed silly to me to run a new harness with much larger wire only to have it terminate with the smaller size. The voltage loss would probably be negligible with only a few inches at the end of the circuit but I chose not to do it that way. The spade terminals I used fit nice and snug. I covered the ends in heat shrink tubing and a round of electrical tape for good measure so if they shift around and contact each other they won't short but having seen multiple melted headlight plugs over the years I worry about how that will hold up over time. I've seen plugs that are ceramic and have 12 ga terminals online so I may order some of those if it seems like heat is having an impact on the harness.

I'm also not very pleased with the reflectors on my new headlight housings. It seems to throw light a little unevenly so there are a few dark spots up close. They were cheap so maybe I'll buy the Hella version which seems to get decent reviews. Does anyone here have a brand preference for conversion housings?
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1985 Tercel 5dr Hatchback
2003 Chevy Suburban
2014 Ford Flex

"I don't get it! I've cut this thing FIVE times now and it's STILL too SHORT!"
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irowiki
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Re: Headlight Relay Harness Upgrade

Post by irowiki »

I don't think many people here have converted... besides from the sealed beams to the 87 composites.
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teranfirbt
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Re: Headlight Relay Harness Upgrade

Post by teranfirbt »

The "diamond cut" conversion lights on ebay are complete garbage, 100% awful. They're also cheap, which is why they're so attractive to people :\.

Having done a few headlight upgrades, there are a few different options. First is Autopal, ~$50 a pair on ebay for the Euro code conversions (don't get the DOT lights, they're better than stock but not by much). Make sure that DOT is not in the description to get the correct lights.

For the price they're 90% as good as Hella lights, and considering normal 6054 bulbs are at least $15 each at the store, it doesn't make sense to buy sealed beam lights over the Autopal E-codes. The *only* reason I can think of is vehicle inspection that actually cares, but I've yet to hear of that.

For a step up, the Hella 200mm E-code conversions are the classic. They put the right amount of light exactly where you need it, but expect to pay $120 or so shipped. IMO not worth double the cost of the Auto-pal lights.

Both the Hella and the Auto-pal have the same annoying issue of lighting up the trees instead of the road on high beam, when the low beams are aimed correctly. It's the down side of a single reflector pulling double duty as high and low beam

For the best in drop in 200mm conversion, Cibie is the only way. They have a more even beam pattern than the Auto-pal or Hella lights, and they worked some devil magic to put the high beam pattern in the right place. They're expensive though, $80 bucks a side, and the only place I know to get them is Daniel Stern.

To get better lighting, you'll need to graduate to projectors. And not the shitty E-bay "projector in a 6054 housing" bullshit, those are garbage. Real projectors will require custom work, either completely new light buckets or some kind of crazy holder that drops into the stock bucket. I had a set of Hella 90mm projectors on my old Celica and they were fantastic. Even lighting from ditch to ditch, ultra sharp low beam cut off, and easily threw light 50% further down the road than the 6054 conversion housings. They're expensive, $60/ea for halogen (and you need 4) or $130 for bi-halogen (but only need 2) plus whatever it costs to adapt them.

Changing gears a bit, let's talk bulbs. H4 bulbs are super common, also called 9003. Don't get anything with a coating, the best ones are clear. For off the shelf stuff, get Sylvania Xtra vision bulbs. 30% brighter than a standard H4 and you can get them anywhere that sells headlights. High wattage bulbs are available, but are not legal, and quality varies. I had a set of Hella 100 watt high/80 watt low bulbs that literally melted a bubble in the glass and burst (ruining my $50 Hella housing :\)

One thing to *never* do is put HID bulbs in a housing that isn't a projector. Projectors are the only housings that can control the amount of light that HIDs put out without dazzling other drivers (or yourself..)

In summary, the best bang for the buck will be a pair of Auto-Pal Euro conversion (NOT DOT) housings with Sylvania Xtra vision bulbs. The best drop in conversion is Cibie housings with 130W/80W bulbs.

Wiring is as important as lights, so follow Mike's advice and get quality relays and 14 AWG minimum wiring to your lights. If you do get E-codes, take some time and aim them correctly, other drivers will be much happier, and you'll get the best performance possible out of your lights: http://www.danielsternlighting.com/tech/aim/aim.html
Notmikeb
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My tercel:: 85 Tercel 5dr FWD
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Re: Headlight Relay Harness Upgrade

Post by Notmikeb »

FANTASTIC info!! That's what I needed to hear. I figured the cheapy housings I got weren't as good but I was more trying for proof of concept first. They are most definitely brighter and in that way a marked improvement over the stock sealed beams but that may be more attributed to the increased voltage at the bulb. The pattern isn't as even though and this morning I noticed there was already some fog inside the glass so I'm sure the housing isn't very well sealed. I will order a replacement set of either the auto-pals or Hellas and update once changed over.

And I second your Sylvania Xtra Vision suggestion. I use them in my Suburban as well and it is the brightest bulb I've found that also seems to last a good long while (4.5 years and 60k miles so far on my Suburban...knock on wood).
Last edited by Notmikeb on Wed Nov 18, 2015 8:24 pm, edited 1 time in total.
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1985 Tercel 5dr Hatchback
2003 Chevy Suburban
2014 Ford Flex

"I don't get it! I've cut this thing FIVE times now and it's STILL too SHORT!"
teranfirbt
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My tercel:: '86 SR5 4WD, 5AFE, lifted rear, 195/70/14 tires
Location: Seattle, WA

Re: Headlight Relay Harness Upgrade

Post by teranfirbt »

Some more thoughts...
Don't cheap out on relays. Unless it says Bosch or Denso on the side, I wouldn't trust it for headlights (your headlights run off them which means your life depends on them).
Bosch P/N 0332 014 112 are 10 bucks-ish each from Rock Auto and are the right way to go. They don't have mounting tabs, but you can get bosch relay holders from ebay for cheap.
Also, don't skimp on wire. The stuff you find at Auto-bone, Napa, or O'Reilly is going to be PVC covered and lowish quality. TXL wire is what you want, it's the current standard for automotive. And do yourself a favor and buy 3 colors, I use red for low, orange for high, and black for ground.
Get quality crimp terminals and the correct crimper. If you get open barrel (OEM style with the U shaped spot for wire), spend the 30 bucks on an open barrel crimper.
Don't forget fuses, those are selected based on wire size. I tend to choose the max amperage my wire can support so that the voltage drop through the fuses is minimized. 12 Ga. can support up to a 30 amp fuse, 14 gauge is good for 25 amps. Modular fuse holders with 1/4" male push on terminals are nicer than in line splice in fuse holders. I avoid splicing wires as much as possible since it's just a failure point.

I think I'll stop now, otherwise I'll be here all night.. When I wire up my MR2 for Megasquirt and headlight relays I'll put together a nice how-to on quality wiring.
Notmikeb
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My tercel:: 85 Tercel 5dr FWD
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Re: Headlight Relay Harness Upgrade

Post by Notmikeb »

Uh oh. I used red wire for high and blue wire for low. Guess I better redo it :lol:
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1985 Tercel 5dr Hatchback
2003 Chevy Suburban
2014 Ford Flex

"I don't get it! I've cut this thing FIVE times now and it's STILL too SHORT!"
teranfirbt
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Re: Headlight Relay Harness Upgrade

Post by teranfirbt »

Sounds like your low beams are going to be sad :P
Terrence the Turtle
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Re: Headlight Relay Harness Upgrade

Post by Terrence the Turtle »

I know i'm reviving a dead tread. but i bought a relay kit. it doesnt work on my tercel but it works on my pickup??? both have leds and the same harness. headlights work as normal without relay.

84 tercel
86 pickup
teranfirbt
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Re: Headlight Relay Harness Upgrade

Post by teranfirbt »

Not sure why it wouldn't at least work on low beam. I had an issue with my Tercel where it wouldn't cut off the high beams until I wired a marker light into the original high beam connector. Somehow Toyota made a simple relay system complicated enough to be current sensitive :-\
Grab a volt meter and start probing, plug in the relay harness and see if it's putting 12v to the trigger terminals 85 or 86.) double check and make sure you're getting 12v at the supply terminal (30). Turn the lights on and off and see if the relays are physically clicking.
Hiro
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Re: Headlight Relay Harness Upgrade

Post by Hiro »

teranfirbt and Notmikeb, I REALLY appreciate the contribution that you both have brought to the forum with your posts in this thread. Thank you for the original post write-up; I can't wait to modify the tercel with improved lighting!

I am a HUGE advocate for being able to (properly) see in low visibility scenarios. One of the common problems include people using brighter bulbs (or HID setups) in a really poorly constructed housing/projector. teranfirbt's post (5th post in this thread) is very conclusive and I agree with everything said there and will echo it.

I have found that whenever possible, go OEM. OEM projectors, OEM HID ballasts, OEM housings, they are all very high quality from the get go and all DOT rated! That's not to say NON-DOT rated items are poor quality; having a DOT rating simply means the manufacturer spent $$$MONEY$$$ on a regulatory house to verify and confirm that their product meets or exceeds government regulatory standards. Just keep in mind you usually get what you pay for.

I have also used the Hella 500 Series lamps (HELLA 005750952) but did not enjoy how narrowly focused this beam pattern was. Trying to be clever, I mounted these to the hood. Never mount to the hood, for they sit on rubber isolators and as much as I tried to mitigate it, the hood vibrated. Lesson learned through trial and error.

Image

After a small fender bender involving a van backing into the front of the car, I was able to finally motivated into executing Rev 2

So, I redid the lighting setup as I wanted a different beam pattern and mounted to the front bumper support, shooting the gap just below the hood with 1/8" angle iron.

I REALLY enjoy my E-code driving lamps that I have on my civic hatch. I pulled the 5-3/4" buckets from a wrecked 1960's Pontiac in the pick-n-pull yard for about $1.00 each and modified them on a custom 2 axis bracket (for vertical and horizontal adjustment) to provide auxiliary lighting to the rather poor OEM lighting option in the civic. The difference is amazingly obvious and the cutoff is fantastic for a daily driver. If you are interested in purchasing some Hella E-codes or other legitimate offroad lighting options, please contact me as I know a very, very reputable vendor who has treated me very well with customer service. I have no affiliation, however, I do try to support local and private businesses whenever possible.

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I share these as to provide some inspiration as you all decide for yourselves how you want to incorporate additional lighting. PM me if you want greater detail on this build and lessons learned in fabricating your own adjustable mounts... I've added/retrofitted custom auxillary lights to other vehicles with success and there's a lot learned along the way.
'86 T2 DLX (114,000 miles and counting)
'90 EE4 RT4WD
'92 EG VX Hatch
'95 YJ 4.0L
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Jonymoto
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My tercel:: 1983, DLX 4wd wagon with 4.1 manual gearbox, tow bar). Manual steering. 313,000 kms. Tercel 4WD SR5, 1987, 500,000kms. Other car - 2003 Rav4, AWD, 2l manual, Peugeot 407 Diesel (93,000 miles) in Ireland for use when on holiday there.
Location: Melbourne, Australia

Re: Headlight Relay Harness Upgrade

Post by Jonymoto »

I don't quite understand your setup. The lights are monuted on the bumper bar, but the electrical wires go through the front of the bonnet. Is that right?
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Hiro
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My tercel:: 1986 Toyota Tercel FWD 5spd

Re: Headlight Relay Harness Upgrade

Post by Hiro »

No. The previous setup was amounted ON the bonnet, so the wires were tucked under the bottom side. The new setups follows the frame rails around to the front and come by right next to the new mounts. When I see a reasonable deal for a replacement hood, the hood will be replaced.
'86 T2 DLX (114,000 miles and counting)
'90 EE4 RT4WD
'92 EG VX Hatch
'95 YJ 4.0L
'05 C6 Z51 (460rwhp)
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Jonymoto
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Joined: Wed May 06, 2015 9:39 pm
My tercel:: 1983, DLX 4wd wagon with 4.1 manual gearbox, tow bar). Manual steering. 313,000 kms. Tercel 4WD SR5, 1987, 500,000kms. Other car - 2003 Rav4, AWD, 2l manual, Peugeot 407 Diesel (93,000 miles) in Ireland for use when on holiday there.
Location: Melbourne, Australia

Re: Headlight Relay Harness Upgrade

Post by Jonymoto »

Ok. For a minute there I thought you had to unplug the wiring prior to openining the bonnet.
When you lose, don't lose the lesson - The Dalai Lama
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