I haven't looked at the manual in awhile, but I seem to recall my L&M HID light had a warning that it could interfere with wireless cyclocomputers (I think if they were placed too closely together). Since I don't have a wireless cyclocomputer, I didn't pay much attention to it....

But now that you mention it, I just checked L&M's FAQs (5th question down), and it does say that electromagnetic interference from the HID will prevent a wireless computer from working. Their suggestion is to mount the computer at least a foot away from the light.