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1967 Lemans 1967 GTO parts car
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Relays are the way to go. I put a 6 relay and fuse box in my cougar. Use the original wires to energize the relays. It's self contained terminal block on on side for inputs and another on the other side a terminal block for out puts. Changing out the vacuum headlight door for electronic. Car stereo and power ports , igition etc. I haven't got that far on the Pontiac yet. But looks like the writing is on the wall that will happen as well.
 

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Relays are the way to go. I put a 6 relay and fuse box in my cougar. Use the original wires to energize the relays. It's self contained terminal block on on side for inputs and another on the other side a terminal block for out puts. Changing out the vacuum headlight door for electronic. Car stereo and power ports , igition etc. I haven't got that far on the Pontiac yet. But looks like the writing is on the wall that will happen as well.
Would very much appreciate a pic of the relay harness.
 

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1967 400/400
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Discussion Starter #25 (Edited)
Here's a diagram of the harness that I made. I used this 2-Pack waterproof relay set and four ceramic H4 adapters from Amazon, that way, it's all plug and play, no cutting any factory wires.

You can tuck all OEM passenger side wires and plugs off to the side. There's no need to use them.

Cut the adapter wires and splice your control wires into them. Use 14g wire and but splice connectors with built-in shrink wrap.





140876


H4 Headlight Relay.JPG

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1967 400/400
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Discussion Starter #26
In a GTO four headlight system, you have 8 filaments, but the factory only uses 6. What you're doing is tying all four highs together and attaching them to one relay. All four lows together and attaching them to another relay. All of the grounds together and grounding to chassis and relays. Run a battery hot to a fuse or circuit breaker, then tee-off to power each relay, and then connect the OEM High Beam wire to one relay and the Low to the other.

It'll blow your socks off. Contrary to what others say, the amount of light and quality that you have, is not what blinds others, it's properly adjusting your headlights. Meaning, this will give you massive light... Whether you choose to blind others or not is up to you.
 

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1967 400/400
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Discussion Starter #27
In my picture, it shows the relay trigger wires coming in from the OEM Headlight wires, but since you'll be plugging the ceramic adapters into the OEM harness, you'll splice off of the adapter wires to trigger the relay. Try drawing it out on paper. I need to take a better screen shot of that cad picture
 

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In my picture, it shows the relay trigger wires coming in from the OEM Headlight wires, but since you'll be plugging the ceramic adapters into the OEM harness, you'll splice off of the adapter wires to trigger the relay. Try drawing it out on paper. I need to take a better screen shot of that cad picture
Great info, very thorough. Wiring is definitely not my deal so pics and schematics are very helpful. Thank you for your help and speedy reply. May have more questions when she's out in the spring. Regardless, will let you know how it went.
 

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I put these in all 4 buckets on my '69. Man what a difference! With these things, at night I can see all the way into next week.

H4 Bulbs
H4 Housings

Just a wee bit of customizing was required on the high beam side. The slots in the buckets for the locator tabs are different between high beams and low beams, and these housings are intended for low beam only. It was an easy fix though. Since the tabs on the new housings are on a separate ring of sheet metal and not part of the glass like they are on regular bulbs, all I had to do was snip off the one tab that didn't line up with the bucket using a pair of sheet metal shears. Also the high beam connector in the wiring harness only has two terminals, but it still connects just fine to the bulb. I wrapped insulating tape around the exposed terminal on the bulb to cover it.

View attachment 139600
View attachment 139601
View attachment 139602
So am I to understand you can convert to these LED by simply swapping the housings and then using the LED inserts? without changing anything else? I really don't want to fry the headlight switch as I have hideaways/vaccum on my 68' and that switch is already a PITA.
thanks
 

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1967 400/400
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Discussion Starter #30
So am I to understand you can convert to these LED by simply swapping the housings and then using the LED inserts? without changing anything else? I really don't want to fry the headlight switch as I have hideaways/vaccum on my 68' and that switch is already a PITA.
thanks
Bear did it, so it "can" be done, however, even though the LED's draw less amperage than the H4's, I do believe that they draw more than the OEM T3. So if your switch is already finicky, I would do the relay harness. It's cheap and easy to make, plus it adds two bulbs and a lot more power to your system, so the improvement will be drastic.

That being said, once you buy the four glass lenses, which accept H4 style bulbs, YES. You drill a 3" hole in your existing buckets and these will pop right in. If you're determined to not use relays, then I would try it, just know that it'll be at least 30% dimmer than it would with relays and the 2nd set of filaments from the OEM high beams.
 

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Bear did it, so it "can" be done, however, even though the LED's draw less amperage than the H4's, I do believe that they draw more than the OEM T3. So if your switch is already finicky, I would do the relay harness. It's cheap and easy to make, plus it adds two bulbs and a lot more power to your system, so the improvement will be drastic.

That being said, once you buy the four glass lenses, which accept H4 style bulbs, YES. You drill a 3" hole in your existing buckets and these will pop right in. If you're determined to not use relays, then I would try it, just know that it'll be at least 30% dimmer than it would with relays and the 2nd set of filaments from the OEM high beams.
Thanks AOD, I might just try it. Need to wrap final piece of restoration though this spring. New UMI rear control arm setup with the factory braces GTOTIGR sold me from this forum (thx Bob!). Then I’ll give it a shot, at least before Hot Aug Nights. Now that she’s painted and all restored after 20yrs, it’s time to show her off. Lost out last summer with this GD pandemic. Blah.
 

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1967 400/400
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Discussion Starter #32
Thanks AOD, I might just try it. Need to wrap final piece of restoration though this spring. New UMI rear control arm setup with the factory braces GTOTIGR sold me from this forum (thx Bob!). Then I’ll give it a shot, at least before Hot Aug Nights. Now that she’s painted and all restored after 20yrs, it’s time to show her off. Lost out last summer with this GD pandemic. Blah.
I was glad that my 70 Vette convertible was on the road for the pandemic. I took a LOT of cruises! But the GTO will be more fun and I can now go shopping with my 78 cubic foot trunk!

I just did front and rear, upper and lower control arms. I used UMI rear uppers.

As for the bulbs, I tried to do it with H4's and no relays. My switch lasted about 2 hours before I lost the lights. Fortunately, they came back on after a cool off, so I could get home. LED's draw less so they will likely work, you just wont get the 2nd filament on the lower (Highbeam) bulb to light.

That's the thing with headlights, wipers, and heat. You can only test them when you're going to be screwed if they fail.
 
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