What would you check in this situation?
I have a handheld GPS mounted on my instrument panel; the Garmin NMEA cable
molded fitting is connected to the GPS. The other end of the wire has a DB9
connector, because it's intended for connection to a computer. To a mating
DB9 connector, I have the bare end of my Furuno radar NMEA cable and a pair
of wires to deliver NMEA to my radio. This has not been changed for many
months - the GPS provides NMEA data to both radar and radio. I occasionally
connect a different GPS to the radio and radar by connecting a Garmin NMEA
cable with DB9 connector to the DB9 connector of the radio and radar.
The last couple of times out, there hasn't been any NMEA indication on the
radar or radio, regardless of which GPS and GPS cable I connected to the
radio/radar DB9.
Today we checked and found continuity in the radio/radar cable and also in
the GPS cable - they both read OK.
The DB9 connectors on the GPS cables are molded and I use dielectric grease
on them (only the 2 and 5 pins are used).
We opened the DB9 connector that feeds both the radar and radio and couldn't
find a short.
We put it back together and thought we'd try again in a few days.
I verified the obvious like the GPSs are set to NMEA, turned on, and had
located our position and that the radar and radio were turned on and set to
receive NMEA. I've decided to replace the DB9 connector on the cable to the
radio.radar even though we didn't see anything wrong because that's the
cheapest thing to replace and I don't know what else it could be.
What would you check?