Stebel horn trips cruise control off

[SpyderCruiser]

I know why you are having this issue. I have the bad boy horn and using the supplied relay. I do not remember if that relay has a surge suppression diode in it but mine does not kick off my cruise. However, my horn is grounded to the frame of the bike, not the battery.

The issue is when you activate the horn, the relay coil closes and the coil charges up (like the primary of an ignition coil). When you let go of the horn switch the coil discharges generating a high voltage inductive spike. This spike can be seen if you ground the negative side of the relay with a piece of wire or test lead. This spike will wreck havoc with the can bus.

I would try first connecting the horn ground to the frame (the horn compressor can generate a spike too). If that does not solve it, you need to connect a diode across the relay coil. Some cube relays have a suppression diode inside, do not remember if mine does.

Here is a more detailed explanation and a diagram on how to place a diode across your relay.

https://electronics.stackexchange.co...ay/56323#56323

Good luck, Louie

[IdahoMtnSpyder]

The issue is when you activate the horn, the relay coil closes and the coil charges up (like the primary of an ignition coil). When you let go of the horn switch the coil discharges generating a high voltage inductive spike. This spike can be seen if you ground the negative side of the relay with a piece of wire or test lead. This spike will wreck havoc with the can bus.

I really think you may have nailed it. I wasn't aware of induced voltage issues with relays but this fits in, and explains more exactly, what I mentioned above about the common ground. The horn button is between the horn and ground. That ground is common with the ground of the CAN bus board in the left and right handlebar switches. I don't think grounding the horn to either the battery or frame makes a difference since the voltage spike caused when the horn button is released goes from the relay coil, jumps the contacts of the horn button, and raises the voltage on the ground side of the horn button and the processor board. I'm sure it wouldn't take much at all to trip up the CAN bus signals from the cruise control board to the VCM.

heynavt1, try replacing your relay with one that has a "flyback" diode included. I'd be surprised if that doesn't solve your problem.

[safecracker]

Spyder cruiser, I was just going to mention if the relay had a diode suppression circuit. All the relays that we use in security systems of today have filters on the relays to prevent voltage spikes. Older equipment was more tolerant. Bruce