AVCC install on '07 wiring questions

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I'm not trying to be a butt here, but I really don't know where you get the idea that it has a "detection circuit" nor how such a circuit wold work. The purple wire is an INPUT into the CC's logic. No volts, OK to engage. Volts, disengage. There is NOTHING ELSE THERE.
How could the purple wire possibly "detect" a blown fuse??!?!?!

The fact that you use the hot side of the brake light circuit for 12V IS the detection circuit. If the fuse is blown, there's no volts, AVCC will not even power up. That red wire is the AVCC's MAIN power. Blown fuse "detected!" Engagement inhibited.

[img=[URL="https://lh3.googleusercontent.com/-ljUahRnblzc/U0__rSAWNII/AAAAAAAANVo/S-5T3PLlkZM/s640/brake%20light.jpg%5D"]https://lh3.googleusercontent.com/-ljUahRnblzc/U0__rSAWNII/AAAAAAAANVo/S-5T3PLlkZM/s640/brake%20light.jpg][/URL]

All I am saying, and all I've said all along, is that connecting the red wire to the hot side of the brake light switch, behind the fuse, is a safety feature, and is the only way the AVCC has to know if the fuse is blown.

If the red wire is connected somewhere else, then the AVCC can engage regardless of the fuse's condition, but the purple wire will never see any voltage to trigger a disengage. There are no volts on that line if the fuse is blown.

If the purple wire sees voltage from something else, some other bleed into the line (as apparently happens on GenII bikes) then the AVCC won't engage, again regardless of the fuse condition or the power source.

But a properly connected AVCC, which may entail a relay on the purple wire, cannot detect the fuse's condition if the red wire is connected anywhere other than behind that fuse. And to me, that's a safety issue. No brake lights, no disengage.
Peace, friend.
First of all,, my lame excuse, I'm on tour Somewhere in Spain or Portugal (depending on which day of the week), suffering from not very good wifi connections using my far-from-ideal phone.

Thought you were talking about a blown (fused?) brake light, not its fuse.

Ok, you are correct, powering the CC from the signalling fuse will guarantee the CC will stop working if that fuse blows. But do remember, if the CC remains powered, and you brake hard, the CC (certainly the Audiovox one, and I suspect others) will notice that it is unable to maintain its control of the speed. If you pull the clutch (not an option with my AS/AE), the engine will rapidly increase its rpm, the CC WILL DISENGAGE. If you don't pull the clutch, the CC will fight the brakes for a bit, but will soon realise it can't maintain speed, and, again, it WILL DISENGAGE. So the system is still "safe".

Oh, just to be pedantic, the "detection circuit" does put out a current. Open circuit that wire, it will disengage the CC, with no external driving voltage. So it's a (weak) output as well as an input.

 
Peace from here, as well. But there's no detection circuit. Pthpthpthpthpth.
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What would it detect? Any voltage put on out the purple wire has only one path to ground, the brake light bulbs themselves. What does the thing care if no bulbs are present? If the wire to the bulbs goes hot, it's happy.

Your description of clutch and brake without brake light detection are correct, but I would not want to apply brakes and have the throttle applied by itself first. Even a little bit.
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You have me curious, though. I can see the logic in having the thing know it has no brake input. if it can't put any milliamps out the purple wire maybe it really can't be happy. I'll test it by cutting my purple wire (temporarily,) finding a nice empty road, and seeing if it will engage. If not, then I will stand corrected and publicly admonish myself for my big mouth. If it engages, though.......
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AVCC purple wire does indeed put out a small amount of voltage/current, as measured by my vom. 4 or 5 volts IIRC. Without voltage, the unit cannot detect ground. Unit needs to see ground to allow engagement. This weak voltage is brought to zero when grounded. Connected to the brake light filaments, the purple wire "sees" ground through the filaments which are grounded. If both brake light bulbs burn out, path to ground is lost, the voltage from the cc unit floats up, showing the unit has no ground on the purple wire. Unit shouldn't engage.

 
Alright alright alright already!
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I tested by removing the taillight bulbs, and sure enough, the cruise refuses to engage. It powers up just fine, but no set.

I'll eat my crow, but it's not very enjoyable.....
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I've been installing these for over 30 years. Every vehicle I've owned that didn't come with a cruise got one, and I've done many for friends. This just never came up. Burnt-out or ungrounded brake lights is not even in the troubleshooting steps in the manual.

On the other hand, the first paragraph of post 13 is false, the information supposedly gleaned from Queensland Ken. There is no "choice" to the type of brake light connection, i.e. which side the ground is on. The red wire goes between the brake switch (or relay) and the fuse, and the purple wire goes on the other side of the switch (or relay.) I'm wondering if that's being confused with the choice of control buttons, whether you use normally open or normally closed switches for on/off and set/resume. That choice exists.

 
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