Wiring my West Marine VHF 480 to my Garmin Echomap 70 GPS using NMEA 0830

[Blueghost924]

Well, I bought this nice Garmen Echomap 74 GPs with internal antenna, and now want to wire it to my West Marine VHF 480 marine radio. Especially for the red button automatic distress call feature. I've tried to wire the harness from the Garmen to the wire harness of my VHF radio in several different wire color arrangements, and can't seem to get the radio to recognize the GPS location from the Garmen.

The Garmen power wire harness has 4 wires: Black, Red, Blue and Brown. The VHF radio ware harness has several different wire color combinations that include green, white, brown, yellow, orange,,,and of course black and red.

Can anyone tell me which color wires I should wire together from the Garmen harness (there's only the blue and brown available) to the VHR radio harness?

 

[sam am I]

Both are NMEA0183 appears............Thats good, same protocol, so

1. Connect the BROWN wire of the VHF 480 accessory cable to the NEGATIVE (-) wire of your
chartplotter’s NMEA data INPUT (Brown)
2. Connect the WHITE wire of the VHF 480 accessory cable to the POSITIVE (+) wire of your
chartplotter’s NMEA data OUTPUT (Blue)


You'll need a backbone bus config though.....Including terminator resistors else it won't work too well.




Cheap way..Near and dear to my heart

http://tekeye.uk/automotive/can-bus-cable-wiring





Better/easier way perhaps

https://buy.garmin.com/en-US/US/p/8737

 

[sam am I]

My mistake, disregard can bus backbone termination stuff above, NMEA0183 is good with just twisted shielded pairs single ended stuff, not differential terminated can bus NMEA2K stuff. Just use twisted shielded pair wiring (see 8.2.2.2) and ya should be good.



https://www.google.com/url?sa=t&rct=...zQ1u97VKDm1-fF



Also, due to Tx/Rx (transmit and receive) of both units and their respective color coding per function and how each are to be config'd in your case, I'll need to make an additional change to the wiring hook ups...A drawing should help, should be done in a sec

 

[sam am I]

Sorry about the confusing lead-up, my bad, my RS-232 just ain't what it used to be. This otta do it though.......Below is more real world however and is how I'll guess you'll wire it based on your post of just having the brown and blue coming from the Garmin.

This assumes the Tx- and the Rx- of the new VHF are wired to ground (similar to the Garmin above, can check them with ohm meter) as shown below.....This internal wiring will have to exist else the data to and from the units won't have a ground reference to work from.

If it still doesn't work (or is flaky/ground looping due to using the boat's ground bus) you most likely have to wire a/the common wire (digital ground, Tx- and Rx -) between the two units as shown above along with the units normal power and grounds as per the install manual.