Aftermarket head unit produces no sound?

Hello, we can pull up the OEM wiring diagrams for the audio system for you. But I need more info on the vehicle, because there are various setups and base vs premium audio systems with a built in amp as well as steering wheel controls.
There is the 3.3liter V6 2wd or 4wd with or without Supercharger. or the 2.4liter 2wd model. And then there is an option for "Base Radio system 2 or 4 door" and then Premium Sound Radio system 2 or 4 door" model. Or you can just post your vin number and we can look it up by that.

There's even a difference between the 2 or 4 door Premium Audio system, the 2 door does not have a additional amp for the rear speakers, but the 4 door does. just to give you an example. This is the 4 Door Premium system, 3.3L V6 non supercharger vehicle. It has an amp for the rear speakers and sub.

My VIN is 1N6DD26T53C458443.

Okay, so. it still gives different options for that VIN.
The OEM diagrams and the aftermarket diagrams are a bit different; do you have 2 or 4 door model?
And how did you wire the 2 subs into the old radio?

It’s the 2-door model and there is no speaker in the rear, only front doors and tweeters. The way I wired the old sub in was through a LOC, but now the sub is completely disconnected because I wanted to figure out the radio situation before trying to wire the subs into the new radio.

Okay, the 1st diagram is the aftermarket 2 door base radio setup; the 2nd is the OEM wiring diagram. The Premium setup has controls on the steering wheel as well. So that's a difference as well. See if these diagrams match the wiring colors you have.

So, that first diagram, the colored one, is the one I've based the wiring off of and those colors match perfectly. I don’t have steering wheel controls for anything. both the lighting switch and the illum ctrl I currently have not hooked up because the new wiring harness doesn’t have any wires for those. i’ll add a photo of the aftermarket harness diagram and how I currently have the wires set up.

I apologize, the red wire is currently hooked up this was before I finished so the picture isn’t up to date, but every wire is currently hooked up except for the illum ctrl and the lighting switch.

Have you checked for 12-volts on the power feeds? I would make sure you have a full 12volts on each, and also verify the ground is good. If you have a 12-volt test light or multimeter.
Something I just noticed on both of these wiring diagrams is this ground, it almost looks like the old radio had some type of case ground, is there a Black wire from the old radio harness in the connector there? It looks out of place on these diagrams.

I don't even see a ground listed for connector M50 or M51, strange.

The thing I noticed when I cut away the old harness was that there was no ground cable. when I wired in the new harness, I haven’t connected the ground wire to anything simply because there is no ground wire from the stock wires to connect it to, but I assumed the new head unit was getting ground somehow considering it turns on fine and works fine just no audio comes from it.

could that be the culprit? I just don’t understand how the old radio would have a ground while the new head unit wouldn’t, when there’s no stock ground wire to ground the stock radio.

Yeah, but it might be grounding through one of the other wires, I would ground the correct wire on the new head unit. It's black, correct? The new head unit might be grounding through one of the speaker wires since they are constantly grounded. Strangely I think the old radio was grounded through the case to that metal case I see in you dash picture.

Check this out.

Okay, I'll do that in the morning. let's say that doesn’t work. What else do you think could be causing the no audio? because seemingly everything is hooked up the same way as the stock HU except for the ground wire.

I would verify you have power on the two power wires, make sure one of those fuses didn't pop. But I think you're going to find this is a grounding issue. Not enough current can flow on whatever path its taking to ground. If its grounding through the speaker wires, there is resistance threw the speakers as well, so ground it and check the 2 fuses if needed.

okay, perfect, i’ll update you tomorrow after I do as said.

Here are a couple of guides for checking power with a multimeter or test light if needed:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

okay, so, I connected the ground wire from the new harness to the negative terminal of the battery using speaker wire (ik there’s ground closer but I decided to use speaker wire because I had a lot of extra and I don’t want to put time into sanding and securing a ground if it's not the problem). There is still no sound. My test light is broken, and my multimeter is dead so I'm going to run to the store for new batteries. The new head unit I'm using isn’t the issue because I swapped it out for the same one and still no sound. if I wired one of the speakers wrong, would that make the whole system not produce noise because if that’s the case I'll go through and re-wire everything again. one other thing I'll include is the blue amp turn on/power antenna is currently not hooked up to anything and I'm not sure what to wire that to because I can’t find a matching one on the stock diagram. Originally, I had it wired up to the ignition/ACC wire in the new harness with the ACC green/red wire in the stock harness but sense then I've unplugged it because it hasn’t done anything differently while hooked up.

Well, it sounds like you hooked up the speaker wires correctly, I mean they're not that difficult. The only other thing I can think of is that the memory power wire touched ground and blew the fuse. The Amp On power wire is just going to be an output wire. This memory wire is hot at all times, so if it touched any ground it would blow the fuse.

Where would that fuse be located? I’m looking at both fuse boxes and I don’t see either fuse 41 or any indication about that wire.

What about that 15Amp Audio fuse?

the Audio fuse is good.

We're missing something here. I would verify full power on the 2 feeds with the key on and use the Ground at the radio for verifying power. Also, what are you using to check for sound, since you don't have the Antenna hooked up? Do you have a cd in the head unit?
I see that the white harness plug is for the new head unit, correct? And you're using crimped connectors, but there looks to be a inline fuse, is that what's on the yellow wire?
One thing I have seen a long time ago was a speaker wire that had somehow become shorted out to the frame where the speaker was located. If I remember correctly, one of the tabs that the speaker wire was hooked to had been bent and was touching the frame in the rear of the vehicle, I don't remember if it cut out sound completely, but it was a problem area and the only time I had ever seen that be an issue.

But check your powers and ground with a meter and make sure there's a full 12-volts, and if after all that still nothing, go through the speaker wiring again.

Sometimes when I run into issues and I'm not 100% sure of a harness connector, I will de-pin a wire I suspect as possibly being the issue and retest. It's much easier than cutting and re-crimping wires. So, you could try de-pinning the right side speak/tweeter and see if audio comes back to the left, and then the reverse. but take a picture of the connector before de-pinning anything so you have a reference for where each wire goes back. Maybe there is a positive and negative switched around. I don't deal with audio issues like this anymore. but the diagnostic process is still the same. Run through what the possibilities could be and then make a plan.
On the back of that white connector, you should be able to see the tab that holds the wire pin into it, that looks like a pretty wide connector. I use a pin or super small flat head to pull up the tab and take the wire out of the connector while testing. But do that after your power checks.

When testing for sound I plug in the antenna, and I also try Bluetooth. correct on the yellow wire there is an inline fuse. you said you’ve seen before the speaker wire shorting because it touched the frame, would that cause the whole audio system to malfunction or just the speaker that said wire is hooked up to. and instead of de-pinning the harness could I just use the multi meter on the harness to see if each of the pins is receiving the correct power.

Yes, I was just mentioning de-pinning the connector to check if volume comes back on either the right or left. So, if you de-pin the right-side speaker and the volume comes back you know there's a problem with the right-side speaker wiring. Or the reverse. But yes, you can just check the power right at the connector, and you should because you need to know power is making it all the way to the radio head.
With the speaker shorting out, I think it did cause there to be no volume at all, I remember it was something I had not seem happen before. And haven't seen it happen since.
If needed, try the old head unit and see if you have volume, this might be a speaker wiring issue. I would go by the OEM wiring diagram I'll repost that for you with the wires labelled.

Here is the OEM Nissan wiring diagram, I marked each wire color for you, the Right door speaker colors could maybe be a bit confusing. But these look to be the same as the aftermarket wiring diagram, but you can double check with this.

okay, so I used my voltmeter, and the right door tweeter is receiving almost no volts (0.1). Should I uncrimp those wires and see if the volume comes back to everywhere else? Should I chase those speaker wires up to the tweeter and see if shorted up there? I apologize for not answering fluently, I've had school and other things have come up.

I would try de-pinning the wires for the right speaker at the connector, you can cut the wires and check the volume then if that's easier for you. I don't think you'll have any shorted circuits to the speakers unless you were working in those areas. But unplugging the right-side speakers first should tell you if that's the problem area. You should get volume back on the left side.

okay. one other thing, the wires that were receiving power were receiving just under 6 volts and I want to make sure that’s the correct voltage that should be read.

No that's not correct at all, both the power feeds should be battery power, the memory feed is 12-volts as well as the ignition switch feed (also 12-volt). You're getting exactly 6volts with the key on? There's an inline connector on the constant battery feed (E43 and M65 are the other side of the connector). The Ignition switch (Acc or on) feed has a connector at the J/B Fuse Block, M26. I'll try to find these connectors for you, but if you have the same exact voltage reading on both wires, your ground is most likely not good. Are you crimping these connectors tight enough? Without a full 12-volts, nothing is going to work right, usually when things get down to around 9-10volt level modules will start to act funny.

Third diagram is the SMJ which looks to be located behind the passenger side kick panel. Here's the locations of everything.

Yes, with the key on it reads just under 6. Once I get back home I'll make sure the ground is strong enough and most of the wires I crimped I had both wires go into the same end of the butt connector and crimped them like that, so the crimping shouldn’t be an issue.

So, I got to the SMJ and I'm confused on what to do. I’m not sure if I read it wrong but am I supposed to test the pins the same way I would with the harness?

You're checking for where you are losing 6+ volts. Are you reading the same exact voltage on the Red/Green wire and the Red/Yellow wire, or just one of the wires? And what's the voltage reading at the two fuses? It seems very unlikely that you would be reading the same exact 6volts coming from two different locations unless it's a battery feed problem to those fuse locations. I put up the connector locations if one of the feed wires was different than the other. You're just checking basic dc voltage feeds. Has the battery voltage dropped off while doing all this installation?

I'm testing the pins on the connector and with the key on nothing is reading other than red/green and red/yellow. now the red/green and red/yellow are reading around 11.2v so last time I must have been using a bad ground. one other thing is the blue wire for the aftermarket HU isn’t hooked up to anything currently and I'm not sure if that should be?

I didn’t mean to send that photo that was meant to be sent 2 messages ago.

Your wire pinout for the blue wire reads "Power Antenna/ Amp Turn-On", so that should be a power output when the radio is turned on. To power either the power antenna motor or an additional Amplifier if you have a box with subs in back that needs a power up circuit. Does the old head unit work if plugged back in? What else do the instructions say that came with the new head unit? I only have information on the stock head unit.

What voltage reading do you get if you use the black wire in the connector as your ground when measuring with a multimeter? And are you getting some different voltage measurement from other speakers than the one you mentioned had nothing on it?

these were the instructions.