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I had a tail light burn out and thought I would replace both the newer LED replacement bulbs (got it on amazon) but it would appear this is incompatible with the cruise control system (at least on my old girl) as I noticed it immediately stopped working.

I put back in standard filament bulbs and it it started working again.

My theory is that something in the LED circuit causes the cruise control to think the brake lights are on thus keeping it from engaging.

Anyone else run into this?
 

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That is a interesting; unintended consequence of installing led's, I guess you could see on a wiring diagram if the circuit is somehow interrelated? One vendor, sells led kits that they claim; have been installed and test on actual Volkswagens, guaranteed to work. Maybe contact them and see what they have to say, they may have run into this during their testing of their bulbs? Would be interesting to track down the problem; please post the: brand, part number and tech specs of the problem bulb. Then possibly, others can tell you what they have installed or tried.

Here is the vendor that sells led kit; they claim are "error free": http://deautokey.com/


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I'll check in on that. I know I've had some odd behaviors with LED lights in my house on circuits that use the X-10 light controllers. The LED light will sometime glow a little.

AND on the bug when I tried LEDs all around the turn signals didn't have the resistance they were looking for so they would blink super fast.
 

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Ok well, I know I'm the new guy and everything - but I happen to know what's up with this one actually. I ran into similar problems on a motorcycle a few years back when I changed all of my turn signals to LED. As soon as I did that, nothing would flash anymore. After I figured it out I became the expert amongst my biker buddies and have since remedied LED-related problems on a dozen or more bikes since then.

The problem you're having is actually the same thing - your LEDs don't provide the amperage necessary to properly interact with whatever relay/sensor/switch is in the cruise control circuit to alert it to whether or not the brakes are on.

Here's why - LED lights are awesome, but electrically - they're completely different than incandescent bulbs. The reason for this is, LED lights effectively draw zero amps. This confuses the crap out of any other devices or circuitry that rely on an amperage draw to activate, such as hazard/turn flasher relays, or cruise control relays. Most electrical switches, relays, etc. rely on current draw to activate.

The good news is, this is very easily (and cheaply) remedied. You simply need to install a load resistor to replicate the amperage draw on the light circuit. It's very simple, very cheap, and requires no major modification or advanced electrical knowledge. You can go nuts and get fancy ones - but basic LED load resistors are like $3 a pop and install in about 2 minutes.

Check this out for full instructions -- How to Install Load Resistors for LED Turn Signal Lights
 

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I had a tail light burn out and thought I would replace both the newer LED replacement bulbs (got it on amazon) but it would appear this is incompatible with the cruise control system (at least on my old girl) as I noticed it immediately stopped working.

I put back in standard filament bulbs and it it started working again.

My theory is that something in the LED circuit causes the cruise control to think the brake lights are on thus keeping it from engaging.

Anyone else run into this?


What model light bulb are you using? I purchased the "brightest LED tailight bulb" they carry (although not satisfied) work perfectly. But they didn't carry that bulb for New Beetles. Fortunately, My buddy works there and we were able to find one that looked very similar to the one pictured on the computer.

Sometimes stuff on amazon is crap.
 

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Yes, I learned that early with my 2000 Beetle - you MUST replace the brake lights with the exact part specified by Volkswagen or your cruise control won't work. Somehow the cruise is routed through the brake lights. German engineering, go figure.
 

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It is probably a safety feature. The cruise control looks for the presence of a few ohms of resistance between the line and ground in order to confirm the connection to the brake light switch.
 

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LEDs will throw codes or cause issues, I had the same issue in my Audi with the license plate bulb and the DRLs


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Well actually the culprit here is not amperage, instead it is the extremely low resistance that most LED bulbs possess.

Our cars have a CCM (Comfort Convenience Module) that controls lighting , power windows, door locks, dome light dimming etc., when most LED bulbs are installed in the interior and some exterior locations, the incorrect resistance is what causes the issues being discussed and can makes the system see the bulb(s) as being blown.

Creating the correct resistance environment when using LED bulbs in these cars, can be tricky.
 

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Having same issue: a few years ago I replaced stock 3rd brake light unit with LED unit from Spyder. I never connected the cruise control failure to the LED installation--it's been a few years and I can't remember when the cruise went out.

Can anyone suggest what ohm/size and number of resistors I should try? There are several options on Amazon. Thanks!

It sounds like I should:
- use reader to check codes
- try contact cleaner on cruise control switch
- check brake lights and switch by pedal
- try installing load resistor on third brake light
 
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