XM radio wiring

[djbroughton]

I spent the morning installing the wiring for my new Garmin 376c. I used the pre-existing black and red wires that serviced the Streetpilot lll that was on the bike (an 02 model) when I bought it. These appear to go straight to the battery as the GPS always has power unless I turn it off. The bike also has an Autocomm Pro M1 system so I ran the 3.5 mm XM "audio out" straight to the "Music input" where I used a splitter to include the existing lead that fed into this. The Aux 2 input also had a wire leading into it and I'm not sure what either of these leads service (both are well hidden in the wiring). Now, when I started the bike up I get really bad feedback from the engine and from the brakes being squeezed. I have a question and a problem:

Question: what are the other wires from the GPS for ie: Port 1 (in and out) Port 2 (in and out) and voice (- and +) and how do I wire these into the bike? I have a pretty good guess what the voice wires are for but where do they go?

Problem: how do I eliminate the feedback noise?

[grahamw]

Dave

Do you still have the Streetpilot? Can you remount it and then check what the 2 inputs are at your Autocom? Call the previous owner and ask him what the 2 inputs to the Autocom are for?

Have you tried it with the bike radio turned off? Unplug the garmin and see if that stops the feedback.

I think you will find the main music input that you put a splitter onto is from the bike radio/cd. Put it back in on its own - turn on the radio and autocom check the sound then unplug it.

I think the other input will be for the original Streetpilot voice prompts - how it will work with continous audio from your XM I am not sure.

When I spoke to Autocom about mounting my PDA they did say that other bike powered equipment can interfere with the Autocom - you may find the other lead used for the original is an isolated lead.

Not sure what you mean by
'what are the other wires from the GPS for ie: Port 1 (in and out) Port 2 (in and out) and voice (- and +) and how do I wire these into the bike? I have a pretty good guess what the voice wires are for but where do they go?'

[Randy]

I spent the morning installing the wiring for my new Garmin 376c. I used the pre-existing black and red wires that serviced the Streetpilot lll that was on the bike (an 02 model) when I bought it. These appear to go straight to the battery as the GPS always has power unless I turn it off. The bike also has an Autocomm Pro M1 system so I ran the 3.5 mm XM "audio out" straight to the "Music input" where I used a splitter to include the existing lead that fed into this. The Aux 2 input also had a wire leading into it and I'm not sure what either of these leads service (both are well hidden in the wiring). Now, when I started the bike up I get really bad feedback from the engine and from the brakes being squeezed. I have a question and a problem:

Question: what are the other wires from the GPS for ie: Port 1 (in and out) Port 2 (in and out) and voice (- and +) and how do I wire these into the bike? I have a pretty good guess what the voice wires are for but where do they go?

Problem: how do I eliminate the feedback noise?You are going to need a "ground loop isolating" audio cable from the GPS to the autocom. All Garmin GPS units use a "floating ground" audio output and will create a terrible noise when connected to the Autocom. You will also damage the Garmin audio circuit if you connect without ground isolation. Here (http://www.autocomamerica.com/product_details.cfm/productid/25638) is the Autocom part for a 2.5mm mono connection good for the voice output for a 2720. I am still looking for part number for the 3.5mm stereo isolator that you need.

EDIT:

Here (http://www.autocomamerica.com/product_details.cfm/productid/25699) is the stereo 3.5mm item.

[djbroughton]

Graham, the original SPIII was only wired for power. The leads into the Autocomm I'm guessing are for the rider and passenger leads. I tried switching them around and also tried the XM alone straight into the Autocomm but still the feedback noise.

As far as the extra wires from the GPS, I just read the manual (which always helps) and it talks about extra wiring for sonar, depth sounder etc. So I'm still curious to know how to wire the voice from the GPS?

The original owner was not at all mechanical and he had the original GPS, Autocomm installed by his dealer.

[djbroughton]

You are going to need a "ground loop isolating" audio cable from the GPS to the autocom. All Garmin GPS units use a "floating ground" audio output and will create a terrible noise when connected to the Autocom. You will also damage the Garmin audio circuit if you connect without ground isolation. Here (http://www.autocomamerica.com/product_details.cfm/productid/25638) is the Autocom part for a 2.5mm mono connection good for the voice output for a 2720. I am still looking for part number for the 3.5mm stereo isolator that you need.

EDIT:

Here (http://www.autocomamerica.com/product_details.cfm/productid/25699) is the stereo 3.5mm item.

Thanks, Randy, I'll give that a try.

[grahamw]

David

Randy's post explains the required lead. All Autocoms that I have seem have the outputs (headset connections) as 5 or 7 pin DIN type fittings on tails coming out of the unit so you can tuck the unit out the way but still get access to attach your headsets. There may also be 3 of these - one a grey coloured one which is an another aux input often used for bike to bike communication.
Any inputs are through 3.5mm stereo type plugs. As you have gathered the 1st input is the sound from your bike stereo - what is the other one for? I would have thought GPS prompts or phone.

I also think you may be unclear about where you want the output to 'appear'

If you are planning to listen to your XM radio a lot do you want the output to come through the bike speakers and headset? if so leave the autocom aas is and look at plugging into the radio and you can then control volume levels by using the AUX channel on your radio. If you do not have an input then this thread has lots of info:

http://www.bmwlt.com/forums/showthread.php?t=4311&page=1&pp=10