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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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17,712 Posts
Discussion Starter #1
I just tried to put the LED's in the front and when I went to test it the driving lights would not come on.

I tried tuning the Headlights on, Just the running lights, High Beams, Starting the Car and nothing worked.

Is it possible the module that controls these lights has gone bad? These lights used to come on all the time but I haven't checked in a while Changed for clear lenses about a month ago so I can't tell when there on from the drivers seat) and I didn't check them before I put the LED in. The Turn Signal portion worked but the driving light would not come on.

I even tried putting the stock bulb back in but still nothing.

Any help would be appreciated on this one.
 

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2006 Light Platinum STS-V - 2005 Black Raven CTS-V (gone)
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277 Posts
Unlike incandescent bulbs, LEDs are polarity-specific. There's a good chance that you [unluckily] installed the bulbs backwards... HA! And you never thought it was so easy to improperly install a lightbulb!

I made the same mistake on one side of the car when I did mine; fortunately, I took the minimally-invasive method by jacking the car up on a lift, pulling the corner of the underbody plastic away (remove only three clips in the corner) and pull out the brake ducts to give your arm some room. It's a job that has to be done blindly, but hopefully you should be able to pull it off... just don't drop one of the bulbs!
 

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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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17,712 Posts
Discussion Starter #4
As I stated in the original post, I have put the incandesents back in and it's still not working. BTW, I only put one of the LED's in for a quick test and the turn signal part worked but the driving light did not so I'm fairly sure it was installed with the correct polarity.

Do you thing something blew? if so what?
 

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2006 Light Platinum STS-V - 2005 Black Raven CTS-V (gone)
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277 Posts
Oooh, I completely overlooked that. Do the rest of the parking lights on the circuit switch on (taillights/rear corner markers), even though the corner bulbs do not? Do the incandecent bulbs flash when you remotely lock/activate the alarm? Is your parking brake set when you're testing this?
 

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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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17,712 Posts
Discussion Starter #7
OK, I tested this with the key on, the key off, Headligts turned on manually, Just the running lights,...

The result was, Side marker lights = on
Rear tail lights = on
Driving lights = Dead

All the lights on the car including those silly little bulbs on the headlight assembly (which I have changed out to LED's) are working.

I think something has burned out but not sure what, I will figure it out tomorrow after work.
 

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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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17,712 Posts
Discussion Starter #8
I have checked the fuses (I think) but I'm not sure which fuse it's on. I am not even sure which circuit the DRL's are part of.

Does anyone have a schematic for the DRL Circuit?

I need to get me a factory manual, Will be calling Luke next week.
 

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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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17,712 Posts
Discussion Starter #10
It's a good question, I was doing this at night but in the garage with the Flourescents on. Is it possible there is not enough light to tell the car not to turn on the head lights?

Well they did work today and I did exaclty what I did yesterday. I disengaged the parking brake and the lights worked, Maybe it has something to do with the Parking brake "and" the Daytime sensor.

This will not happen to me again (I hope).

Thanks for the help Nikon, Reed and Imperator.

One last question, What is the best way to slow down the flasher when you change to an LED?

I don't like the idea of as load resistor, no better then the flashers. The electronic flasher seems like the way to go but becuase GM decided to make this such a fancy module it makes it difficult to change. I am thinking about disabling the flasher in the DRL unit and adding an elctronic flasher but I need all of the schemaitcs before attempting this to make sure I don't screw up another part of the circuit.

I have searched the internet with not much luck. Does anyone have a schematic of this DRL unit?

Do you think it might be in the factory manual?

Thanks for the help.
 

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05' CTS-V
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I haven't looked into it, but...is it just a standard 2-3prong flasher unit??? If so just replace that one with one that won't blink quick...I forget the wording but they it at most autoparts places....otherwise you might be stuck with a load resistor...unless you really want to dive into changing all the electronics around.....and as for the florescent lighting, sometimes it'll set it off, othertimes it wont...usually I take my drop light and shove it on the dash, takes away any guess....you could also have known if your nav screen said headlamps suggested when you disabled the e-brake....either way, glad you got it working and let us know what you do with the turn signals....If you do decide to do a load resistor, superbrightleds.com sells them in a nice sealed (weatherproof) little package for not that much $$.
 

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2007 CTS-V Thunder Gray; 2004 Cowboy Cadillac (SRT10)
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Discussion Starter #12
Learned something interesting about the Falsher in the V.

Unfortunetly it is part of the DRL control unit so there is no way to replace it. The good news is it is electronic and not thermal. When I turned on the Hazards the flash rate was correct.

There is a frequency doubler that is somehow triggered by the the current draw (or lack of) and I think I'm close to figuring out how to eliminate it. The good news is if I hose this module up it only cost about $30 to replace it. If it works then I'm sure there may be a couple of people that might be interested in the mod.

Don't like the idea of the extra current darw and the Harness mod if it's not required.

I do appreciate the ideas and I hope I can figure this out.
 
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