Brighter Headlight Mod.

[vrg3]

They're not the most common type. Most automotive relays are the Bosch-type, with a terminal configuration that looks like this:

http://www.rps4wd.com/tech/relays.htm

[mikec]

Cool. Thanks for the clarification Vikash.

[boostjunkie]

Hmmm, I'm wondering how beneficial this would be to my stock lighting system? I know the low beams are an H7 projector, not sure about the bulbs for the highs. Vikash, how noticeable was the difference in light output after this mod?

[vrg3]

It was definitely noticeable. I can't quantify it, but I don't know of anybody who's upgraded their lighting circuit on a Japanese car and not been pleased with the results.

Unless Toyota has changed their old habits, your Celica's lighting circuit is still probably pretty shoddy. Just test it -- measure the voltage across the H7 bulb while the engine is off and the headlights are on (and the bulb is lit). Compare it to the voltage across the battery terminals. Knowing that luminous flux of a halogen bulb is proportional to like the 3rd or 4th power of voltage, you can estimate how noticeable a change will be.

I think your high beams use 9005 bulbs.

[boostjunkie]

I'm going to be doing this upgrade! I took a look at the wiring at the socket connector for the low beam H7. It's as shoddy as every other Japanese car out there. Something like 18/16gauge! I found a GM alternator socket connector that fits the H7 connectors too! I figure that harness should be sturdy enough for an upgraded headlight harness.

I read the link posted earlier about the Toyota wiring for their headlights. Do you think you could take a look at the wiring diagram and tell me whether or not the circuit is a positive or negative switched circuit? I believe the pertinent info is on page 7.

http://www.radphys.com/WIRING_DIAGRAM_FULL.pdf

I was gonna hold back on the high beam until I got enough money for the harness. I only have enough to do the low beam and the fogs (since they're the lights I'd use on a regular basis).

Two more things. An H3 foglight setup. How would the wiring setup differ for this? I know the bulb is usually gounded to the body of the foglamp, right?

Also, the stock foglamp is a glass lens, so I'd be able to run a higher wattage bulb without melting the housing. Do you have any recommendations for a higher wattage bulb that actually puts out more lumens than a standard wattage bulb?

[vrg3]

I remember doing this on a Camry once, and I think it was switched ground.

These diagrams are kind of hard to read, but from looking at page 25 I'd say it does look like your Celica's got a switched-hot setup.

But if you wire it the way I suggest earlier in this thread, you don't have to worry about whether it's switched-ground or switched-hot. Just stick the relay's coil in place of the bulb abd you'll be fine.

It also appears that you don't have a normal headlight circuit in your car. Your headlight switch doesn't control the headlights. It tells the "body ECU" that you want the headlights on, and the computer is the responsible for actually flipping the lights on. That may or may not matter... If your car has "bulb out" idiot lights on the dash they might falsely come on if the computer doesn't like seeing relays instead of filaments. Or if there's some kind of weird failsafe mode that the computer goes into, that could get weird. I guess you'll just have to try and see, though.

That's neat that a GM alternator plug fits the H7 bulb. Way cool. Does it provide enough protection from moisture and stuff? I'd imagine so, since it's for an alternator, but you never know with the General...

It's smart to first do the low beams. They're the ones that need it most.

You can upgrade your fog light harness if you want, but don't get overwattage bulbs. Increasing the light output isn't really consistent with the purpose of a fog light. But yes, H3 bulbs usually ground via their base through the body of the lamp, so you probably can't really improve the ground side of the circuit too much.

[boostjunkie]

Okay. I'll just run the relay's coil in place of the bulb.

The GM alternator socket doesn't REALLY fit an H7 bulb. Imagine that you have the two spade connectors facing the same direction within the housing. The two prongs that stick out from the bulb (actually the bulb socket connector that's attached to the bulb itself) contact one side of the set of spade connectors. The other prong wedges itself between the plastic of the socket connector and the back of the spade.

Kinda hard to explain without a picture.

As for the H3 unit, since the bulb is grounded to the body of the light, if I were to route a ground connection to the body of the foglight, would that make any difference?

Oh yeah, the reason why the ecu is integrated into the light circuit is because the celicas have a instant-on headlight. There's a sensor on top of the dash that picks up light. When there's not enough light supplied to the sensor the headlights come on automatically.

Unfortunately, this function was disabled when I disabled my daytime running lights.

[vrg3]

Hmm... I think I understand what you're saying about the socket. Are you sure that'll make a good solid reliable connection? Normally you nearly surround the prong with the other contact; merely pressing against the prong from one side might not do it. It'd suck to have a really nice heavy-gauge wiring harness end in an inadequate connection to the bulb.

Yes, it might help to run a ground strap from the engine block to one of the fog light's mounting bolts... You could just try it with a jumper cable first to see if it makes any difference.

[DeusExMachina]

Where did you get the relays for this? I think I want to do this on my '91

[vrg3]

You can get standard Bosch-type automotive relays at most auto parts stores or electronics stores.

[boostjunkie]

Vikash, I ended up just taking some spade connectors and using those as terminals without a "connector" housing. Just put electrical tape and shrink tubing over the ends to make sure the two spade connectors didn't short each other.

I tested the voltage drop across the driverside bulb. The battery was reading 12.2V. The upgraded harness was reading 12.2V and the stock wiring harness was showing 11.3V. So there was about a 1V differential between the two setups. Not sure how much this will help, but we'll see tonight. Kinda hard to tell when it's sunny outside.

[vrg3]

That connector setup sounds fine as long as it doesn't admit moisture. You should put dielectric grease in the female spades before connecting them (if you haven't already).

12.2 volts should give you about 25 to 35 percent more luminous flux than 11.3 volts. I'm sure you'll be pleased with it when the sun's not competing.

Cool.

[DeusExMachina]

Vikash, what are the amp ratings on the relays? Or just any automotive relay?

[vrg3]

Most good automotive relays will be rated for 30 or 40 amps. This is a good deal more than the current they'll actually be carrying (figure about 5 to 10 amps per filament depending on wattage) so that's fine.

[DeusExMachina]

Okay. Cool. Also, can I step up the wattage on the bulbs? What temp would the housing melt?

I bought from Advance two 9004 connector pigtails, looks to be about 12 or 14 gauge wire on it. I also bought new bulbs (figured I should anyway, and were on sale) so I'll cannabalize the old ones for connectors.

What gauge wire would you recommend for all the connections, also?

[vrg3]

No, you can't reasonably step up the wattage, for numerous reasons. A search for posts I've made about the 90-91 headlights should yield most of them.

New bulbs are a good idea. All bulbs' performance declines with age. That's what makes a lot of people think crappy bulbs aren't crappy -- they put them in and can see better, but that's just because the bulbs are newer than their old ones.

What kind did you get? All 9004 bulbs are not made equal. The "best" ones you're likely to find are Sylvania Xtravisions.

12 or 10 gauge should be good. I chose 10.

[DeusExMachina]

Thats what I bought. Sylvania Xtravisions.

Thanks Vikash for the help.

[vrg3]

Excellent. You're welcome. =)

[IronMonkeyL255]

This thread is just chock full of useful info.

Is it just me, or does anyone else think this should be stickied?

[boostjunkie]

That connector setup sounds fine as long as it doesn't admit moisture. You should put dielectric grease in the female spades before connecting them (if you haven't already).

12.2 volts should give you about 25 to 35 percent more luminous flux than 11.3 volts. I'm sure you'll be pleased with it when the sun's not competing.

Cool.

Actually, I rechecked, and ity seems the battery's putting out 12.2V while the upgraded wiring is putting out 11.9V. The stock wiring is putting out 11.3V. So it's a little bit less luminous flux. However, I noticed that the lights are a little "whiter," with the output cutoff (edge of the light projection) is a lot more pronounced.

The H3 fogs were actually grounded to the body like the headlights, so I upgraded those. I think a lot of the voltage increase is from my wiring the ground connection for the lights through the upgraded grounds I have from the battery (4-gauge). So there's a 4-guage ground that goes to the body a lot closer to the actual light that it's grounded to.

Do you know where I could get a fused relay? I've seen these before (I think Hella makes applications) but I can't seem to find them on a websearch. I want to make the install a little prettier.

[vrg3]

Hm, so you've still got some voltage drop through the headlight wiring... That's not good.

I'm not sure I understand what you're saying about the grounds. Are the headlights grounding through the chassis? Cuz maybe the remaining drop is on the ground side then -- you could try measuring the voltage from the negative side of the bulb to the negative battery terminal to see.

I don't know a good source for fused relays... Try emailing Daniel Stern. He's a knowledgeable guy so maybe he knows where you can get them, or maybe he can source them himself.

[boostjunkie]

Checking the voltage drop I found that the ground side (that I had soldered a connection to) wasn't exactly perfect. I went ahead and resoldered the connection and now I only have a .02 voltage drop.

[vrg3]

Cool... That's pretty good then.

I just realized something to point out about fused relays -- in order to get the full protection of the fuse, you'll have to mount them very close to the +12v source. Remember that the wire going from the alternator or battery to the fuse is unprotected.

[IronMonkeyL255]

I got a pair of 9004 plugs at Autozone today. About $3.39 each. They only have about 16 gauge wire coming out, but I think I'll switch that out for 12.....

I also picked up a pair of weatherproof inline fuse holders that were made with 12 gauge wire.


I went into Advance looking for the connectors and they were telling me to get the Silverstars.

One guy said they had 'burned the yellowing off of the inside of his headlight lens' and the girl there was convinced that I was upgrading to higher wattage bulbs.

I gave up trying to teach them.

[evolutionmovement]

Still better than the ~20 ga wire I've seen on a new Beetle.

Steve