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Will resistors restore my cruise control with LED brake lights?

Old 09-19-2012, 04:57 PM
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Default Will resistors restore my cruise control with LED brake lights?

I have searched and searched and haven't found an answer on this... when I installed LED towers as my brake lights, the cruise control would stop working when the running lights were turned on. Another problem the LEDs created was the LED brake light on my SS spoiler would come on all the time, albeit very dim. Will resistors fix either of these problem?
Old 09-20-2012, 02:43 PM
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Anyone know?
Old 09-20-2012, 02:57 PM
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Had the exact same issue with my '02 Camaro, but never tried the load resistors to find out if they would fix it. Putting the stock bulbs back in instantly cured the problem, so that leads me to believe that the load resistors would likely fix your issue. Sadly, I think you are going to have to try it to find out for sure with no guarantee that it will work.
Old 09-21-2012, 03:53 AM
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have you tried electronic flashers? .......and no...not EL12s
Old 09-21-2012, 07:51 AM
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Originally Posted by Latch
Another problem the LEDs created was the LED brake light on my SS spoiler would come on all the time, albeit very dim.
I have this issue only when my hazards are on. The Libby light will come on very lightly - but hard to notice.

I figured there is some sort of inductance or bleed-over in the circuit which causes this but haven't had the motivation to tackle it.
Old 09-21-2012, 07:53 AM
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Originally Posted by sjsingle1
have you tried electronic flashers? .......and no...not EL12s
This is definitely not a flasher issue...I had fully electronic flashers, and they did not address this issue at all. It wouldn't matter in this case anyway due to this being a Camaro - the turn signal bulbs are separate from the tail light bulbs, which is what he's having problems with.

The issue is that the circuit was designed with a filament bulb load in mind, and the cruise control interrupt circuit must use that in some way to determine whether or not the brake lights are on. Brake lights on = cruise control off. When the LEDs are installed in this application, you'll note that the 3rd brake light will be dimly lit, indicating that there is current flowing through the circuit even though the brakes aren't depressed. The likely fix is to install a load resistor in the circuit to absorb the small amount of current that is allowed to pass through the LED tails, but I never actually tried it to find out.
Old 09-21-2012, 07:57 AM
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Now could this be my reason my cruise doesent work at all? hmmmm... i got the same problem ive had the LED brake lights for a while now and never thought of that.. som beeech
Old 09-21-2012, 08:41 AM
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Originally Posted by 216StealthSS
Now could this be my reason my cruise doesent work at all? hmmmm...
Ummm... definitely not.
Old 09-21-2012, 11:11 AM
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Originally Posted by wssix99
Ummm... definitely not.
Old 09-21-2012, 01:23 PM
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It most certainly is the cause of the cruise not working, BTW it's not just limited to our cars. Do a Google search for "cruise control LED brake lights" and you'll find the same problem being discussed on Civic forums, Eclipse forums, Silverado forums, and others.
Old 09-22-2012, 01:25 AM
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i have LEDs in my 3rd brake light also......but they dont come on unexpectedly
Old 09-23-2012, 09:20 PM
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Originally Posted by Latch
It most certainly is the cause of the cruise not working, BTW it's not just limited to our cars. Do a Google search for "cruise control LED brake lights" and you'll find the same problem being discussed on Civic forums, Eclipse forums, Silverado forums, and others.
Is there really a case where this has happened on an F-Body? The GM manuals say specifically that the module looks for a positive voltage coming out of the brake switch.
Old 09-23-2012, 09:34 PM
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Originally Posted by wssix99
Is there really a case where this has happened on an F-Body? The GM manuals say specifically that the module looks for a positive voltage coming out of the brake switch.
Yes, it did it to my car. The cruise control does work in the daytime when the running lights are off. As soon as the lights come on, no cruise. I put my regular bulbs back in and no issues.
Old 10-04-2012, 11:35 AM
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I know this is an older post but oh well. If you guys wire one way diodes in line of your brake lights then when you turn the park lights on it won't back feed 12v into the system and make the 3rd brake lamp come on and your cruise will work after dark. I would have to look at the wiring diagrams on my computer to tell you what would be the easiest place to do it but you could do it at the rear light harness connector.
Old 10-04-2012, 09:32 PM
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Thanks for the comments folks. I was going to buy LED brake lights just for the fun of it but it seems like they're more trouble than they're worth.
Old 10-05-2012, 10:04 AM
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Originally Posted by CamaroAJ
I know this is an older post but oh well. If you guys wire one way diodes in line of your brake lights then when you turn the park lights on it won't back feed 12v into the system and make the 3rd brake lamp come on and your cruise will work after dark. I would have to look at the wiring diagrams on my computer to tell you what would be the easiest place to do it but you could do it at the rear light harness connector.
Uhhh... no. Good idea in theory except that the parking/running light circuit isn't connected to the brake light circuit except that they share a common ground. And the CHMSL (third brake light) doesn't share that ground (unless you count that they all ground through the body/chassis somewhere). If the circuits were connected, you would have a back feed problem just as much with regular bulbs as with LED replacement bulbs.

The symptom you describe could happen if the tail/brake bulbs had no ground connection. The current from the tail lights would then try to ground through the brake light filament, back feeding the circuit. However, the solution there is to restore the correct ground, not to add a diode.
Old 03-31-2013, 02:44 PM
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ok so i know this is a bit of an old thread, but i've got a decisive answer (I've fixed this very same issue just now).

Just to be clear - my issue was that after I installed LED tail lights (Anzo, if you were curious), my cruise control stopped working. Turn signals were a-okay, it was just the cruise that was messed up. After a lot of Googling, I quickly figured out that putting in a resistor of some sort somewhere would fix the problem...didn't get any real clear answers, but I figured it out - so here it is!

I got a couple 25W 6ohm resistors from autozone (they have a little kit specifically for this purpose - look in the light bulb section). The kit comes with 4 wire taps, as well. You don't have to cut any wires or anything, it's very easy.

- Pull the carpet back in the trunk, exposing the wires on the driver's side.
- Pull back the electrical tape on the bunch of wires there, and find a light blue one, and a black one. You will see the black one goes directly to a bolt in the center of the trunk for a body ground.
- Using the wire taps, connect the light blue with the black ground wire with the resistor. Be sure to leave yourself a good bit of wire to make it easy to mount the resistors somewhere safe (more on that later). I bought a coil of 18 gauge wire for this purpose, as well as a few more wire taps.
- Mount the resistor somewhere safe using steel zip ties (plastic might melt, those things ger really freaking hot. I mounted mine in the middle of the trunk by the latch, on the metal, away from any carpet.

Think of the resistor as the light bulb. It's serving the very same purpose (providing resistance in the circuit), and get's hot, just like a light bulb (but it gets way hotter).


^^ This is for the driver's side. The passenger's side is the same idea, but you have to take the brake light off to access the light blue/black wires. There's a hole in the body for you to conveniently feed the wires through, so it's really easy.

I will stress again the importance of mounting the resistors safely and securely. Steel zip ties are available at Walmart and lots of other places I'm sure...so get those and you should be good to go. If you aren't sure about anything I've said and are doing this yourself, feel free to PM me, and I'll provide pics and try to explain it clearer...I kinda rushed through this post so I'm not sure if it's 100% clear. I did this earlier today, and everything works 100% right, even my turn signals, so this will certainly work. Also, I'm not an electrician. If somebody here is, and you see something wrong/stupid, PLEASE PLEASE correct me. I don't want to spread bad information!

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Old 12-06-2016, 12:27 PM
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I just bought a 2002 Z28 SS Convertible and wanted to update the running lights to LED and found the same problem; I lost cruise control with LED brake/taillights.
I think after looking at this thread that just leaving my incandescent bulbs in is the best solution. If I add load resistors, and it creates a bunch of heat, no benefit.
Old 12-06-2016, 08:43 PM
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I do have LEDs in my taillights, but I never use Cruise Control so I have no clue if mine still works.
Old 12-08-2016, 12:45 AM
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Originally Posted by rickeagle
I just bought a 2002 Z28 SS Convertible and wanted to update the running lights to LED and found the same problem; I lost cruise control with LED brake/taillights.
I think after looking at this thread that just leaving my incandescent bulbs in is the best solution. If I add load resistors, and it creates a bunch of heat, no benefit.
Did you change out the flashers?

I have LED's on my 02 SS in the front corners and all the rear lights. I changed out both flashers. Cruise control works just fine with my set up.

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