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Rostra cruise issue


Hi, all. I installed a Rostra cruise control on my 2009 C-14 per Fred Harmon's wiring diagram. I'm using a Rostra control switch, with an engage light. I was very careful and all of my wire taps are hard-wired solder joints. The cruise control works, but intermittently. When I first start out, the cruise will engage when I press the S/C button (but not the R/A button). When I tap the brakes, it shuts off the cruise completely, and I have to turn it back on, sometimes several times, to get it working again. However, after riding for a while, everything works as it should, i.e., I can tap the brakes or pull in the clutch, the cruise disengages and re-engages with the R/A button. What the ????

I have done the diagnostic check of the control switch, per the manual, and all voltages check out on the servo side of the 4-pin connector. However, I cannot get it to go into diagnostic mode. The LED light comes on and stays on. Per the manual troubleshooting instructions, I checked my main ground, brake-light ground, and No. 12 switch position, and they are all fine. I've run out of things to check.

Any suggestions would be appreciated.



In order to get into the diagnostic mode, the clutch disengage wire needs to be disconnected.

On my install, the brake light relay, and the "engage light" relay are tied to the same ground point, up on the sub frame. Try putting those grounds together. Not sure if this will fix the issue, but it might. Turning completely off is rather strange (when brake is hit), and then working after it warms up. It may be that the voltage is coming completely up to 13.8 volts after it has been charged for awhile. Might want to check your battery.

I have had issues on other bike where the relays I was activating (On my C10 with murphs Lights, and wiring harness kit) had strange behavior until they shared the same ground.

The ground for the Rostra unit itself went to the battery ground.

When you first start out, that is how my cruise works as well, there has to be a set point before the R/A will function.
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