Nissan Altima installation problems

Plug the OEM stereo back in to verify that the system in its stock state still works properly.  If it doesn't, then there may be a fuse blown.  Make sure to continuity check all fuses with a multimeter, including ones under the hood.  Also it's possible that a speaker wire is shorting out somewhere.  Check all the wiring behind the dash first before even considering to take off the door panels and stuff like that.

I'm pretty sure that the factory amplifiers use a high level input and therefore wouldn't need to be bypassed when installing an aftermarket head unit;  also, they shouldn't need any special integration adapter either.

I would tell you how to bypass the amp but not only do I think it's not going to be necessary, but if they really are 2 ohm factory speakers your Jensen head unit might not be able to handle powering them.  It's always possible that it might work, but I personally would not recommend such a setup.  However, if it comes to that point and we've exhausted all other possibilities, I'll give you some detailed instructions on how to go about doing it.

Just FYI, the amp on the driver's side under the rear deck is the amp for the front speakers, and the one on the passenger's side is for the rear speakers.  Here's a picture that tells you a lil more about the rear amps.

The OEM stereo no longer works. That’s why I got the Jensen as a replacement . The OEM unit had no display, or power. I gather from your web site that this does happen with the 94 Nissan Clarion OEM head units. Because the cup holder is so close to the stereo, I took it apart, expecting to find shorts in the various boards. I found no obvious damage to any of the components inside the radio. I didn’t take the faceplate apart, so I’m not sure about that.

After checking junkyards for a replacement, I discovered I could get the new (2.0 DIN) Jensen for about the same price. Seemed like a good idea at the time…………..

Getting a display in the new head unit is an improvement, but the no sound output part kinda stinks.

I continuity-checked all the fuses (under the dash, under the hood, the two 10-amp fuses in the amps), they all checked out. I also checked the harness for damage/potential shorts and found none. Do you think the problem could be in the amps? I did get the HU to push (6-ohm) speakers from a home stereo when I jumped them to the rear speaker harness of the wiring adapter (main harness connected to radio through vehicle, rear harness disconnected and jumped to speakers).

I pulled the dash apart looking for shorted wires. Also pulled the doors apart. No shorts.

Then, I plugged the OEM head unit back in, and the strangest thing happened. The HU came alive when I plugged the antenna in. Everything works as it should. When I shut it off (by power button or key) the head unit dies. It works again if I unplug the antenna, then plug it in again. Could a shorted antenna lead cause this ? Is the problem in the head unit?

Incidentally, I still can't get the new HU to work. At this point, I'll settle for the original, if I can get it working. Any suggestions?

The reason the OEM head unit worked when you plugged the antenna in is because a lot of times they can use the antenna cable to get a ground.  but it's not the most reliable way to go about it and I'd make sure that the aftermarket head unit's ground wire is run to a good grounding spot back there behind the dash.

Unlike the aftermarket head units, the oem one will not have a ground wire coming out the back of it.  If I had to guess I'd say that the OEM head unit's chassis has to be touching a grounding point for the vehicle (such as the metal mounting brackets) in order for it to get a proper ground.

As for getting the aftermarket one to give you sound...I thought of one more idea.  Plug it in to the factory wiring, and test for voltage on all of the wires in its harness.  In particular I'd focus on any extra wires that exist on the factory side, but not on the wiring harness adapter that you purchased.  Other than the switched 12 volt wire, there should also be one that would show 12 volts when the system is turned on, and 0 when it's turned off.  Once you find that and know it's not the switched wire for the radio, hook up the jensen's blue wire to this factory wire and test it out.

If you have any other questions about your altima go to Altimas.net

They have anything and everything about Altimas.