Installed new JVC headunit into 1989 e34, not getting any sound

[moonsspoon]

I just purchased a new JVC headunit (KD-HDR50) to replace the OEM tape player in my 1989 e34. After installing, everything works except I am getting no sound out of my speakers. The amp turns on when the radio turns on, a faint amount of hiss comes out of the speakers when the headunit is turned on. The hiss does not fluctuate with the volume control though, meaning the JVC unit is not likely sending ANY signal to the amp.

Since the old radio uses a common ground, the write-up I was using said to combine all the grounds/negative speaker wires together. Will this not work with this head unit? Without re-wiring/bypassing the factory amp, is there anything I can do?

Thank you.

[Binjammin]

It's a pain in the ass. From what I can recall, there was a loop that needed to be grounded to the body of the head unit when I put the JVC unit in my car.

[zubbie]

I've seen 2 versions. One says tie all grounds together (speaker and chassis) the other says tie all chassis grounds together but leave the speaker negatives hang unconnected.

I'd try them both before rewiring. One of the versions worked for me but the sound is still attenuated somewhat (nakamichi HU) I'm ready to say F%^& it, rewire, new amp and 4 component the whole thing.

[moonsspoon]

I've seen 2 versions. One says tie all grounds together (speaker and chassis) the other says tie all chassis grounds together but leave the speaker negatives hang unconnected.

I'd try them both before rewiring. One of the versions worked for me but the sound is still attenuated somewhat (nakamichi HU) I'm ready to say F%^& it, rewire, new amp and 4 component the whole thing.
I'll try leaving the speaker negatives disconnected. Thanks.

Edit:
This worked perfectly. HD Radio sounds amazing. Thank you. You've ended the awful mood I've been carrying around all weekend.