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Ok, Im going to try to not be too long winded. And if there's another thread already discussing this, please point me in that direction.

Ive converted all my 1157 bulbs in my 1966 GTO to the proper LED replacements. Even spent the $ and got the correct flasher for said LED bulbs. Now for my issue... The brake light, tail lights, rear turn signals work amazing. Very happy with that. The front is where my issue lies. The marker lights work fine but BOTH front turn signals flash at the same time, no matter which way I flip the arm. Everything worked fine with all the old bulbs. So, I know the wiring of the car is fine. Do I need to ground something? Do I need a different resistor somewhere to make the fronts work properly? Has anybody else done this and run into this issue? Im open to suggestions.

Thank you ~ Phil
 

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Ok, Im going to try to not be too long winded. And if there's another thread already discussing this, please point me in that direction.

Ive converted all my 1157 bulbs in my 1966 GTO to the proper LED replacements. Even spent the $ and got the correct flasher for said LED bulbs. Now for my issue... The brake light, tail lights, rear turn signals work amazing. Very happy with that. The front is where my issue lies. The marker lights work fine but BOTH front turn signals flash at the same time, no matter which way I flip the arm. Everything worked fine with all the old bulbs. So, I know the wiring of the car is fine. Do I need to ground something? Do I need a different resistor somewhere to make the fronts work properly? Has anybody else done this and run into this issue? Im open to suggestions.

Thank you ~ Phil
Sounds like you have a switch problem as you are energizing both circuits. Did it work properly before the LED conversion ?
 

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Yup. Everything worked perfect before swapping bulbs. I messed around with it a little more last night. There is a small amount of current running through the opposite side of which your signaling. As in, with the right side signal on, the test light flashes on the left socket. With the left side signal on, the test light flashes on the right, as well. It's very faint on the test light but more than enough to fire off the LED. Ground issue? Not enough resistance?
 

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I wish I had an answer for your crossed circuit problem, but I am curious about your choice of LEDs for the tail lights. I tried some out, but because the bulk of the LED modules are on the end of the "bulb" and our tail light bulbs stand vertically within the light capsules, mine ended up no brighter than the incandescent 1157s. In other words, most of the light brightness was directed straight up and not out through the tail light lenses. Did you find some LEDs that project out the side of the bulb, instead of the end?
 

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Ok, Im going to try to not be too long winded. And if there's another thread already discussing this, please point me in that direction.

Ive converted all my 1157 bulbs in my 1966 GTO to the proper LED replacements. Even spent the $ and got the correct flasher for said LED bulbs. Now for my issue... The brake light, tail lights, rear turn signals work amazing. Very happy with that. The front is where my issue lies. The marker lights work fine but BOTH front turn signals flash at the same time, no matter which way I flip the arm. Everything worked fine with all the old bulbs. So, I know the wiring of the car is fine. Do I need to ground something? Do I need a different resistor somewhere to make the fronts work properly? Has anybody else done this and run into this issue? Im open to suggestions.

Thank you ~ Phil
If the rear t/sigs work separately as designed, that pretty much eliminates any problem in the t/sig switch itself. Particularly given the fact you're getting some voltage to the "wrong" side, I'd bet nickels to nuclear warheads you've got a ground issue in the front end somewhere. It may have been there all along, with the heavier load of the 1157's possibly masking the problem.
 

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Discussion Starter #6
Yeah, I found these bulbs and they have the diodes on the face and all around, as well. Not sure how to post a picture on here but they seem like a decent piece. Ill dive back into this when I get a little more time. A ground issue sounds (at this point) like the most plausible cause, to me. Ill keep checking back and if I find the issue, Ill post it. Might help someone else. Thank you, guys
 

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Ricker:
Just a quick question: Are you trying RED LED bulbs in the back and not white? I learned this lesson. Something about which color light that the lenses are meant to pass. Sounded weird to me but it turned out to be true. Mine is a 67.
 

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Hudlow66:
Chased the same problem on my 67 (or it chased me). Never did get it figured out. Went back to incandescent. I'm too old for this shit.
 

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FWIW; Been using the 2357R for about a year now much improved light out put with NO side effects to stock system.
Did you change only the rear bulbs to LED, or front and rear? I'd like to change the rear only but did not know if that was possible. Thanks for the pictures. Very helpful.
 

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Did you change only the rear bulbs to LED, or front and rear? I'd like to change the rear only but did not know if that was possible. Thanks for the pictures. Very helpful.
You should be able to just go with LED at the rear with no issues. I used a mix of LED and filament bulbs on my brother's truck - no issues.

You most likely will have to change your flasher unit to a newer electronic style flasher. I also did this on my brother's truck.

There are different styles of 1157 LED bulbs with regards to the placement of the LED chips. I use an online supplier called Super Brites LED https://www.superbrightleds.com/cat/led-vehicle-replacement-bulbs/ You can check out the offerings as to the different types/styles. They provide dimensions and the angle that the LED light will project its light. Some of the "towers" may actually be taller than the standard filament bulb, so you may want to measure. If too tall, they have "mini" which is shorter.

You will see several offerings to choose from, like cool, natural, & warm. I thought the number you see with each box, ie 6500, 4000, 2950, was the brightness level. I found out not so. The "natural" is what you want if going with a clear/white light as it is the brightest of the three choices. The colored choices are what they are. You will see the lumins which is how bright they are.

Never had any problems and they ship very fast. So just a choice to take a look at.
 

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Did you change only the rear bulbs to LED, or front and rear? I'd like to change the rear only but did not know if that was possible. Thanks for the pictures. Very helpful.
Yes just the Bulbs on the rear.
I will add that I also applied a coat of High Temp Flat White paint to inside of the housing.
This worked far better then any Silver to help increase output.
 

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Rear Leds

Yes just the Bulbs on the rear.
I used the Super Brites 1157 CAN Bus LED Bulb - Dual Function 30 SMD LED Tower - BAY15D Bulb - Red
Part Number: 1157-R30-CBT
I also upgraded with their led flasher relay.
I could not believe the difference, Absolutely worth the money.
If you have the age cracks in your lens as most of us do, these are awsome..
 

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Two reasons for switching to LED:
1) safety, i can be seen much easier by people, first time i drove the car with wife following she stated the brake lights were dim, they were fine shes used to the brighter ones of today.
2) less drain on my old electrical wiring.
I'd like to discuss the the latter. I've noticed a light load resistor kit is required is required at each bulb to mimic the resistance of an incandescent. Doesn't this put the strain right back on the wiring?
https://www.superbrightleds.com/items-added/?pc_id=12851&quantity=1
 

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Hi John
I did not add any load resistors to my 67 GTO taillights, just the replacement flasher and they work flawlessly.
No regrets here.
 
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