KyleG

Here is want I received back today " Thank you for contacting Garmin Aviation Support. In regards to any interaction between the GNX 375 and the SL 30 per the installation guide there is no interaction between the two units. Kind Regards," Looks like I will be running a RS232 out from the area 660 to the SL30 then. Shoot!

Thanks Oscar! After 2 weeks and 10 hours of flying i'm re-visiting your post. I have been flying with Music on the GMA345 from my phone via bluetooth which has been great. The down side is in order to get AHRS, Traffic, weather to my 660 I need Blue tooth from the GNX375 which I cannot get because I'm trying to bluetooth the 660 to the GMA345 for the audible alerts. I have found out in the last few weeks the GNX375 does not give audible alerts. I find it crazy that the aera 660 has more functions than the GNX375. Although the GNX does give display alerts. The other side of the coin is I like to bluetooth data to my phone with garmin pilot which gives me full flight data logging with attitude and altitude via the GNX375. Somewhere along the way I need to pick which is the most important. I'm leaning on the GMA345 to my phone for music and phone calls and then having everything else hard wired like you say. The other issue I have is in the Aera 660 manual, the barewire connector displays a left audio, right audio and common audio. on the GMA345 there is a Music Left/right pins but this would mean overriding my Bluetooth music/phone selection, picking Music 1 or Music 2 on the select button on the GMA345. I'm think maybe I have to take the common Audio and pin it to AUX1 HI pin or wire it to an Alert pin. The only down side to the alert pin is I cannot select it on or off on the audio panel. I left and email with Garmin to see if the unit GNX 375 can output frequency data to my SL30. No reply yet, but I would feel more comfortable with the information coming from my certified product other than the portable 660. I'll keep you posted Kyle

Thanks Brad!

Thanks for posing this Brad! I'm still trying to learn and figure everything out. How are you getting the Century A/P to follow the flight plan? I see your radio coupler is selected to HDG but on your DG it's ignoring your heading bug. I just got mine out of the shop on Friday and have played with the G5 and Heading mode but have not had time to play with the GNX 375 Navigator much. Appreciate your help so much!

Follow up to this thread. on 6-7-2019 I put everything back together. Did my ground check and had the same issues but they were not as prominent as before. (Maybe the shield grounds having better continuity to the aircraft frame helped) Anyways I did my full ground check and then turned off my G5 and reprogrammed it to the Century A/P setting instead of the AutoControl setting the G5 has. Bingo!!! It works perfect now! Flew it down to Avionics shop on Monday after putting 3 hours on it this weekend. I Love this G5 interfaced to the A/P Can't wait for the GNX 375

Thanks Oscar. You are correct that was my original goal. My hopes were to have the Area 660 interface with the SL30 and the G5 HSI and then have the GNX375 interface this the G5 HSI as well as the 660. It seems I'm getting conflicting information from my Installer on what I can and cannot do. I asked him how long they have been doing installs and he said for almost 2 years now. I also asked what it took to be a Garmin partner. He said a one week course down in Kansas and some money and he was good to go. Been doing this for 2 years now! He is not a pilot so I understand why the things I ask don't make sense to him yet. My current A&P AI friend that helped with the G5 install seems to know more and has also fixed other issues from 3 avionic shops in the midwest. I guess no one is perfect.

I had the installer leave the SL30 on its own. It gives me a to/from reading with the bearing right on the unit which is pretty nice. I still have a King KX155 with a KI-209 glide slope for Radio #2. The installer called me today and said he wired the GNX 375 direct to the G5 via the rs232 and now he just needs to do the ARINC 429 to the Gad29B. I asked him why the GNX needs to use ARINC? He just said thats' what the manual displays. I'm pretty frustrated with this process. I like to understand my equipment in the plane and how it's interfaced and working. Yet I feel the industry of Certified G.A. has a kiss and don't tell attitude. Guess I'll have a learning curve here next week.

I forgot about the STC. I was thinking maybe Garmin or some other manufacturing would have a RS232 to ARINC429 Converter that would be able to send the secondary data to the instrument. I'm still trying to learning all these bells and whistle and thought the data selected could be made right on the G5. However over the last few days I see the data needs to be driven directly from the unit and not the G5, hence the STC makes perfect sense for not allowing more than 1 coupled navigator.

I spent the evening trouble shooting the interface harness. To be sure it was not a AutoPilot error, I hooked up the old DG directly to the CD-33 Female plug with the current new harness spliced in. (I had the new harness completely unhooked and isolated) This by passes the Radio coupler completely. I ran the plane up and turned on leveler... All good. Turned on HDG and moved the old DG heading bug to the left... it checked out.... moved it to the right and it checked out. No issues with the old system. It has to be the in the new wire interface. I really did not want to pull it apart but had to. I did all continuity checks and ground checks to make sure there where no shorts. I pulled apart the D-sub to the Gad29B and went to do my continuity check when I found Pin 14 was not seated all the way. (I'm embarrassed to say this) I pushed the pin in and temporarily put everything back together. Turn on plane and did ground check again. When the G5 Loads up and I turn on the wing leveler now if follows the heading bug no problem. This is great but sure is not right as I do not have the HGD selected on the AMP. I'm glad the interface harness is talking with everything but I still can't figure out the issue here. The only other test I can think of doing is removing the pigtail connection and putting back on my old DG for a Radio Coupler check. The other test I think I'll run tomorrow is turning off my nav radio while doing the test to see if there is any interference. I'm still not sure why the system goes hard left when I turn on the HGD switch yet follows the bug under wings level configuration. If anyone has any trouble shooting idea I'm all ears. Thanks for the help!

Thanks Jesse, I spoke with Garmin and they said the same thing. I'm a bit confused as the fellow at Garmin said the newer GNC255 has both ports out, the RS232 and the ARINC429 which would allow the G5 to play fair with both. I'm not sure I understand how that would work exactly but I'm leading toward having the GNX375 coupled to the G5 and leave the SL30 by its self. The SL30 does have it's own navigation information on the unit display so a separate Nav display I feel is not worth the money.

HI all, I'm trying to finish up a G5 HSI install and thought I would post a few notes. Looking for some help and hope to give others some help. I have to give a big thank you to @bradp He has really gone the extra mile with the century AP wiring and parts list for me. I contacted my local friend who is an A&P AI and he decided to supervise me with this install. Truth be told he did at least 60% of the work and told me what to do. Because every install is different he was stumped on a few things, as was I. The interfacing of the Century Auto pilot to the Gad29B is not the clearest I feel. Dealing with many transformers, resistors, inductors and capacitor seems to be a bit confusing to me. The G5, Gad29b, and the magnetometer where straight forward as my supervising AI has done a few of them already. The issue has been with the AP interfacing which i'm still having issues with. I had to take the Garmin diagram attached and lay it out with him. We then made a drawing of everything and followed in to detail. I also leaned on @bradp for this. The biggest question or confusion is the polarity of the resistors and tank circuit. There was no label in regards to the direction the circuits needed to be interfaced. Note 3 on diagram and Note 4. After the install and G5 Flight Control setup we went for a test fly. "Nothing" happened. Wing leveler work as normal. But Radio coupler does not pick up the heading bug on the G5. I hope to pull this wire harness apart this week and find the gremlin causing this issue.

Thanks for all the replies. What kind of switch do you guys use? I would think the shop would be willing to interface this for me. I have the GAD29B, and wonder why Garmin doesn't have the GNX375 point to that to drive/interface with the G5 HSI. I also have an area 660 I wanted to couple to my SL30 but my locale A&P AI said it would cause the same issue. Would need to disconnect the SL30 from the G5 just so I could run the SL30 from the touch screen of the 660. This is a little frustrating.

Hi All, Kyle here. Long time reader but first time posting. I have been going back and forth the last month with my recent upgrades. I had a Garmin G5 HSI put in with my Garmin SL30. Love the G5! The issue I'm having now is the RS-232. I have a shop installing the Garmin GNX375 next week. However they tell me the RS232 from my SL30 will have to be removed from the G5 so the GNX375 can couple to it. This will leave my SL30 Nav worthless unless I purchase a stand alone indicator. Not that I don't trust the shop (I kind of don't) but to me there as to be work around by Garmin. Any tips or ideas would be greatly appreciative.