Need help with Nissan radio

I have been having problems with my 95 Nissan Altima CD/Radio/Cassett (stock Alpine system). It quit for no reason over a month ago. I took it out to check it. Checked all fuses, relays,etc.. When I reinstalled it, it worked for 1 or 2 cycles (turning it on, then off).

Then it wouldn't work untill I unplugged the antenna, then plug it in again. I bought a new head unit and tried installing that, but it wouldn't work either. The stock one works for a few cycles after unplugging/plugging the antenna.

Last time I went through this, the battery was dead when I was finished, so I jumped the car to start it. When I tried to turn it off with the key, it wouldn't shut off. I hit the brake, and the engine died. This reminded me about a remote starter we had installed 1 1/2 years ago. It never worked consistently (always had to be re-coded), so we shut it off and forgot about it. I took it back to where I  got it and had them take it out, figuring it had screwed up my wiring.

When I put the stock radio back in, it worked for 12 cycles (on/off). I figured it was OK, so I put everything back together. Sure enough, now it won't work. I know it will work if I pull the dash apart and unplug/plug the antenna lead, but only for a while. I am at my wits end trying to figure this out, is my ignition wiring screwed up? It starts consistently and runs fine. Its just the radio that doesn't work. Please help, at this point I can't see how I'll ever get any radio to work in this car.

Yes, it's all factory wiring.

I thought the ground was ensured by the factory radio brackets, which are attached to the chassis behind the dash.

I will try running a seperate ground wire to the firewall.

Thank you both for your input.

There may be something wrong with the nissan head unit, but you should definitely be able to get an aftermarket unit to work for sure. Just make sure you use a wiring harness (Metra 70-1763 or 70-7550, verify the correct one by looking at the pics).  Also, there is no ground wire in the factory harness so you have to hook up the aftermarket head unit's black grounding wire to a spot of bare metal somewhere behind the dash opening--usually screwing into the back of those mounting brackets will work fine.  If you do not run this separate ground wire, the head unit may at first seem to function normally, but at some point down the road you'll likely have it die on you due to an insufficient ground.

Well, I tried grounding the radio chassis to the car chassis with a seperate wire.

The results are exactly the same. The new Head Unit will not work, and the OEM Head Unit will work for awhile, then quit.

I've given up on the new one, but it would sure be good to get the old one to work consistently. Every time I shut the ignition off, the OEM HU shuts down. When I pull the dash apart and unplug/replug the unit, it works (for awhile).

After almost 2 months of this (taking the dash apart 50 or so times), I'm losing hope. I was hoping someone out there would know about some obscure relay (or other component) that would explain this.

If anyone out there has any ideas, please let me know. I'll try anything.

Are you test the unit on a battery charger or directly on the battery? Be sure you do not groung off the speaker wires or the power wiers.

Let me know what happens.