Anyone running two GPSs on a J&M MA-967 amp?

[Bionic Pelvis]

I have the J&M MA-967 amp hooked up to my Zumo as my primary audio source. I want to add a second GPS, and when I'm done I want to Zumo to remain as my primary audio source, with the second GPS breaking in with routing instructions.

It seems that it should be pretty straightforward to wire the second GPS into the MA-967 radar detector connectors. Anyone been down this road before?

Specifically, I'm wondering if the unit acting as the secondary audio source has to be powered through the MA-967 radar detector plug in order for the audio to work. My experiments wiring expendable electronics into the audio plug only were fruitless. I am supposing that one of the two ground wires running to the radar power plug is sending confirmation to the amp that there is a second source from which to start listing for audio input. If no one has sorted this out before me, I'll have to move on to testing on things that will make me much more angry if they start smoking.

I asked tech support at J&M if such a thing were possible, or if they had other generic non-radar harnesses available that would make this kind of thing easier. The response was, "Yes, I suppose it would be possible. If you wired it up right. Which would be a lot easier if I had a wiring diagram for the MA-967. Which I don't." Not an entirely useless response, I suppose. I took it to mean, "You're on the right track, but I sure as hell am not going to provide you with written proof that I helped you void your warranty."

Your help is much appreciated!

 

[fjrrider]

All I can tell you is how I have mine hooked up. Zumo 550 and TPS radar detector all tied to a Kennedy "radar override". Radar detector comes first, followed by the chick in the zumo, then music. Which with the Zumo comes XM radio, and MP3 tunes. Works perfect, even in the rain. One side note carry xtra 9V battery for the override.

 

[Bionic Pelvis]

Alrighty, for the hundreds of you who have lost sleep over this issue... I have your answer. Yes, it is possible to wire in a non-radar audio source into the radar hook-ups.

The radar hook-up consists of two two-pin connectors. The first has two black (ground) wires going into one pin, and a red (switched hot) wire going into the other. My experiments lead me to conclude that your audio source DOES have to be powered through the amp (unlike your primary audio source), so be sure to wire your power up here.

The second connector has black wires at both pins. One is a ground, the other is you audio signal. With the connector clip on top, looking at it from the non-harness end of the connector, the left wire is the ground. Of course, if any of the throngs of interested parties are going to attempt this themselves I would recommend throwing a multi-meter on yours just to confirm. I modified a heavy duty headphone cable to end in the appropriate connector.

The end result is that my Zumo is on all the time, for phone calls and music and so forth. The 2730 cuts in whenever it is giving me driving directions. The only thing to take note of is that I had to change the 2730 audio jack setting from "Headphones" to "Line Out". On the headphone setting, the signal was too weak and would break in and out. With the line out setting, I have a good strong signal with clear audio.

 

[Bionic Pelvis]

One more update to this riviting and wildy popular topic (Hey, you never know - someone may come here searching for just this exact information. Someday.)

Through some additional fiddling, I have discovered that you actually DO NOT have to wire the power through the amp in order to get sound through the radar lead.

The power connector has two ground wires. In fact, one ground wire goes to ground and the second loops over to the audio input connector. My amp had an open on that loop, inside the wiring harness. When I was attempting to wire in just the audio, it was not working because I had no ground. An incidental tug of that wire pulled the loop out of the harness and revealed the problem.

SO to summarize:

Wire you stuff into just the audio, or wire it in to both the audio and the power. Heck, wire it in to just the power. Whatever floats your boat.