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Home » Public Forums » GMCnet » New LED front turn lights not working right... (park lights during day ok, no turn at night...ugh)
New LED front turn lights not working right... [message #355942] Sun, 21 June 2020 09:12 Go to next message
Shawn Bennear is currently offline  Shawn Bennear   United States
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Registered: February 2007
Location: Edinburg, PA
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I recently installed a set of front LED parking/turn signal lights... I am having a wee bit of an issue, as follows...
during the day the turn signals work perfectly fine. turn on the parking lights, and that's all I have. no more turn signals. I do have the electronic flasher installed, and they work fine during the day. turn the lights on, shows over.

Trying to figure out whats wrong with it. Do I need to hard wire instead of using the socket?


http://www.gmcmotorhomeworld.com 1977 Palm Beach, 403 V8 w headers.
Re: New LED front turn lights not working right... [message #355943 is a reply to message #355942] Sun, 21 June 2020 09:57 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
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Registered: April 2006
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C. Boyd
76 Crestmont
East Tennessee

[Updated on: Sun, 21 June 2020 12:58]

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Re: New LED front turn lights not working right... [message #355945 is a reply to message #355942] Sun, 21 June 2020 15:43 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Location: S.E. Michigan
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Shawn Bennear wrote on Sun, 21 June 2020 10:12
I recently installed a set of front LED parking/turn signal lights... I am having a wee bit of an issue, as follows...
during the day the turn signals work perfectly fine. turn on the parking lights, and that's all I have. no more turn signals. I do have the electronic flasher installed, and they work fine during the day. turn the lights on, shows over.

Trying to figure out whats wrong with it. Do I need to hard wire instead of using the socket?
Shawn,

Be patient, I am sure we can figure this out.

Did you install a single replacement for 1157 LED in an OE front marker / signal light housing?
You say it works with the marker lights off, but please give a better description of what happens when you turn on the marker lights.
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?

There is a very high (outrageously high) probability that there is a bad ground in the marker light assembly. I have had to build in a new ground on all of mine.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: New LED front turn lights not working right... [message #355966 is a reply to message #355945] Sun, 21 June 2020 20:28 Go to previous messageGo to next message
Shawn Bennear is currently offline  Shawn Bennear   United States
Messages: 43
Registered: February 2007
Location: Edinburg, PA
Karma: -1
Member
Matt Colie wrote on Sun, 21 June 2020 16:43
Shawn Bennear wrote on Sun, 21 June 2020 10:12
I recently installed a set of front LED parking/turn signal lights... I am having a wee bit of an issue, as follows...
during the day the turn signals work perfectly fine. turn on the parking lights, and that's all I have. no more turn signals. I do have the electronic flasher installed, and they work fine during the day. turn the lights on, shows over.

Trying to figure out whats wrong with it. Do I need to hard wire instead of using the socket?
Shawn,

Be patient, I am sure we can figure this out.

Did you install a single replacement for 1157 LED in an OE front marker / signal light housing?
You say it works with the marker lights off, but please give a better description of what happens when you turn on the marker lights.
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?


There is a very high (outrageously high) probability that there is a bad ground in the marker light assembly. I have had to build in a new ground on all of mine.

Matt

Matt, No, I installed the whole complete one with about 30 led's in it on a circuit board...

http://www.cruizers.org/lights.jpg


http://www.gmcmotorhomeworld.com 1977 Palm Beach, 403 V8 w headers.
Re: New LED front turn lights not working right... [message #355972 is a reply to message #355942] Sun, 21 June 2020 23:51 Go to previous messageGo to next message
bwevers is currently offline  bwevers   United States
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Registered: October 2010
Location: San Jose
Karma: 5
Senior Member
The 1975 schematic shows two circuits with 1157 bulb. The park
light filament is wired to the same circuit as the side marker lights.
The park lights are low intensity filament (purple wire).
The turn signal is wired (blue wire) to the high intensity filament.

Maybe the two input wires to the new LED lights are swapped so
that you always have high intensity when the park lights are on.
And the turn signals are low intensity.



Bill Wevers GMC49ers, GMC Western States 1975 Glenbrook - Manny Powerdrive, OneTon 455 F Block, G heads San Jose
Re: New LED front turn lights not working right... [message #355974 is a reply to message #355966] Mon, 22 June 2020 07:25 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
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Senior Member
Shawn Bennear wrote on Sun, 21 June 2020 21:28
Matt Colie wrote on Sun, 21 June 2020 16:43
Shawn Bennear wrote on Sun, 21 June 2020 10:12
I recently installed a set of front LED parking/turn signal lights... I am having a wee bit of an issue, as follows...
during the day the turn signals work perfectly fine. turn on the parking lights, and that's all I have. no more turn signals. I do have the electronic flasher installed, and they work fine during the day. turn the lights on, shows over.

Trying to figure out whats wrong with it. Do I need to hard wire instead of using the socket?
Shawn,

Be patient, I am sure we can figure this out.

Did you install a single replacement for 1157 LED in an OE front marker / signal light housing?
You say it works with the marker lights off, but please give a better description of what happens when you turn on the marker lights.
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?


There is a very high (outrageously high) probability that there is a bad ground in the marker light assembly. I have had to build in a new ground on all of mine.

Matt
Matt, No, I installed the whole complete one with about 30 led's in it on a circuit board...
Shawn,
That is a nice looking part, but you still did not completely describe the issue:
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?
Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: New LED front turn lights not working right... [message #355980 is a reply to message #355974] Mon, 22 June 2020 09:44 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
Messages: 372
Registered: February 2004
Location: St Augustine, FL
Karma: 1
Senior Member
Matt Colie wrote on Mon, 22 June 2020 08:25
Shawn Bennear wrote on Sun, 21 June 2020 21:28
Matt Colie wrote on Sun, 21 June 2020 16:43
Shawn Bennear wrote on Sun, 21 June 2020 10:12
I recently installed a set of front LED parking/turn signal lights... I am having a wee bit of an issue, as follows...
during the day the turn signals work perfectly fine. turn on the parking lights, and that's all I have. no more turn signals. I do have the electronic flasher installed, and they work fine during the day. turn the lights on, shows over.

Trying to figure out whats wrong with it. Do I need to hard wire instead of using the socket?
Shawn,

Be patient, I am sure we can figure this out.

Did you install a single replacement for 1157 LED in an OE front marker / signal light housing?
You say it works with the marker lights off, but please give a better description of what happens when you turn on the marker lights.
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?


There is a very high (outrageously high) probability that there is a bad ground in the marker light assembly. I have had to build in a new ground on all of mine.

Matt
Matt, No, I installed the whole complete one with about 30 led's in it on a circuit board...
Shawn,
That is a nice looking part, but you still did not completely describe the issue:
Do the lights come on and stay on (on, but no flash)?
Or, do you just get nothing?
Matt




If I remember correctly there is an issue with using LEDs in the turn signal/front marker light circuit.
The side marker light gets it's ground from the filament of the front turn bulb and the LED will not allow the reverse path like a incandescent blub will.
Look thru the archives I think there is a solution there.



Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
http://www.bdub.net/tomlins/
Re: New LED front turn lights not working right... [message #355981 is a reply to message #355980] Mon, 22 June 2020 09:55 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
Messages: 372
Registered: February 2004
Location: St Augustine, FL
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Senior Member
https://groups.google.com/forum/#!searchin/gmcnet-archive/led$20turn%7Csort:date/gmcnet-archive/YUH0_WbiH58/alOaqYM5AgAJ



Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
http://www.bdub.net/tomlins/
Re: [GMCnet] New LED front turn lights not working right... [message #355996 is a reply to message #355981] Mon, 22 June 2020 13:08 Go to previous messageGo to next message
powwerjon is currently offline  powwerjon   United States
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Registered: March 2013
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Senior Member
Tom,
Your are correct on the front side marker/turn signal. It does not work with LED’s in the side marker position because of way the circuit is designed. I have standard bulbs in this circuit. I run all LED tail light assemblies in the rear with out issue and do run a mechanical flasher unit in both position on the steering column.

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan

> On Jun 22, 2020, at 10:55 AM, Tom Lins via Gmclist wrote:
>
> https://groups.google.com/forum/#!searchin/gmcnet-archive/led$20turn%7Csort:date/gmcnet-archive/YUH0_WbiH58/alOaqYM5AgAJ
>
>
> --
> Tom Lins
> St Augustine, FL
> 77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
> Manuals on DVD
> GMC Dealer Training Tapes
> http://www.bdub.net/tomlins/
>
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Re: New LED front turn lights not working right... [message #369357 is a reply to message #355942] Sat, 02 April 2022 12:06 Go to previous messageGo to next message
EricWaS is currently offline  EricWaS   United States
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Registered: August 2020
Location: Spokane, WA
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Junior Member
When installing LED bulbs for the turn/brake light signal system, you must use electronic flashers, and the front side marker lights need to be "non-polarity" sensitive. The front parking light switches the ground on the side marker light during the flashing process, so if it is polarity sensitive, it will not work. If you look at specs of the bulbs they will generally specify this, but if they don't, assume that they are polarity sensitive. I never would have guessed these bulbs even existed, knowing LEDs are typically polarity sensitive! Mine all work correctly now after learning and doing this.
Re: New LED front turn lights not working right... [message #369358 is a reply to message #355942] Sat, 02 April 2022 12:27 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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Senior Member
Eric,
Non-polarized LED's have either a built in bridge rectifier or two sets of LED's wired with the polarities opposite each other.

It was a neat trick how GM wired the front side lights that way on their vehicles.


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: New LED front turn lights not working right... [message #369363 is a reply to message #355942] Sat, 02 April 2022 14:21 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Bruce that one gets ‘em every time. The GM engineer design parameters were not for LEDs at some future date. Right up there with the designed high blower over voltage trick by design. Me, I’m fine with incandescent lamps in classic vehicles and love the warm look.

John Lebetski
Woodstock, IL
77 Eleganza II
[GMCnet] Re: New LED front turn lights not working right... [message #369364 is a reply to message #369363] Sat, 02 April 2022 14:51 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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I got an education on polarity when I converted my GMC 78 Royale's
clearance lights on the roof. I bought all new led lights and hooked one of
them up and turned the power on, and nada, nuttin', and scratched my head
and exclaimed Wth!. So, out comes my trusty Fluke 77 and it told me the
story. No rhyme or reason to the wiring. Polarity on all of them was
different. So, turn on the power, check the polarity, hook up the led,
repeat x 10. Same is true throughout the whole 12 volt system in the coach.
Incandescent's don't care about polarity. Led's definitely do. Now I check
first, then proceed.
Jim Hupy
Salem, Oregon

On Sat, Apr 2, 2022, 12:21 PM John R. Lebetski
wrote:

> Bruce that one gets ‘em every time. The GM engineer design parameters
> were not for LEDs at some future date. Right up there with the designed high
> blower over voltage trick by design. Me, I’m fine with incandescent lamps
> in classic vehicles and love the warm look.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
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> GMCnet mailing list
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Re: [GMCnet] Re: New LED front turn lights not working right... [message #369366 is a reply to message #369364] Sat, 02 April 2022 16:05 Go to previous message
Matt Colie is currently offline  Matt Colie   United States
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James Hupy wrote on Sat, 02 April 2022 15:51
I got an education on polarity when I converted my GMC 78 Royale's clearance lights on the roof. I bought all new led lights and hooked one of them up and turned the power on, and nada, nuttin', and scratched my head and exclaimed Wth!. So, out comes my trusty Fluke 77 and it told me the story. No rhyme or reason to the wiring. Polarity on all of them was different. So, turn on the power, check the polarity, hook up the led, repeat x 10. Same is true throughout the whole 12 volt system in the coach.
Incandescent's don't care about polarity. Led's definitely do. Now I check first, then proceed.
Jim Hupy
Salem, Oregon
Fortunately, when I mounted the first of the LED clearance lights, I turned it on because I was curious what it would like like. It didn't. Also fortunate was that was one of the few where I could get to the connectors. So I reversed the polarity and it looked good. I mounted the other nine powered up.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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