From Garmins owners manual...
"Radar Service Lost—(radar) the unit has lost communications with the remote radar unit. Check
the network and the radar wiring".
So... first thing I would check is your ethernet, (net work) cable. Make sure the connectors at both ends, (display and radome) are completely seated. Un-thread the cable protectors, (ring) and make sure the connectors are completely "snapped" in. If your using an expansion box, check from dome to box to display.
Also, who ever did the install may have done a "field connection" on the display or expansion box end... meaning, they had to cut the connector off, to route the cable thru any hardtop piping and then re-attach the supplied connector. Those ethernet connectors can be tricky and need to done just right. There are eight wires, (connections) in those little "phone" style connectors and every one has to be perfect. If for some reason they didn't use Garmins supplied connector, it can be even more difficult, because a lot of the generic, after market connectors won't seat properly in the socket. I had a situation where I had to grind off the locking tab, in order for it to completely seat.
After that I would check the connections for the power cable to the raydome. Check any crimp lugs that may have been used and tighten any connections. If there's an in-line fuse, and you already have a spare place on a fuse/circuit breaker panel, then you don't need the in-line fuse... get rid of it, (they are unreliable). I would not be surprised if this were your problem, (power related).
If all the cables check out, the only other thing I can think of is.. update or re-install your software. I don't know which model you have, but I do know there were some software updates relating to the "hd" radar units. You can contact Garmin and they will assist you with downloading any updates. You'll need a blank memeory card of course.
