Aftermarket headunit powering on but no sound

[meatwad]

Hi all,

 

I have installed an aftermarket headunit (Atoto F7) in my 1999 LE with Bose factory amp using Scosche harness # NN07B. This harness is supposedly specifically for factory amplified Nissan systems. The wiring was fairly straightforward and the unit gets power, but no audio is delivered to the speakers.

 

I suspect this is an amp issue (not powering on?) but I’m completely lost on how to go about fixing it. 
 

Also, there are two separate wires for ground on the Scosche harness. There is a chassis ground (black) and amp ground (black + white). I have tried connecting each of these independently to the ground wire (black) from the headunit and still, power but no sound. 
 

I must be missing something. I’m admittedly a complete noob when it comes to car audio so any advice would help. Thank you

[meatwad]

Update: 

 

I spliced the amp turn on wire (blue + white) in with the red ACC wire to ensure power is being delivered to the amp. I can hear a slight pop and a continuous quiet hum while touching the wires together so I’m assuming the amp is receiving power. Why it’s not putting out sound is beyond me

[Slartibartfast]

I see that your head unit and adapter connect using RCA plugs. I haven't set up a head unit like that, but the first thing I'd do is poke around in the owner's manual to see if there's some some setting you need to change to switch it over from the internal amplifier to the RCA outputs. I would also double-check that the RCAs are plugged into the correct holes--looks like you want the four closest to the power plug on the back.

 

If it's not that easy, check fuse #4 (15A), in fuse box JB (looks like that's the one under the dash). That's the unswitched power feed for the audio system, and while the head unit may power up without it (it also gets power from the ignition switch), the audio amps (there are actually three of the little blighters) will not. If that fuse is blown, check your work, because fuses usually blow for a reason. Check your color code match-ups, look for damaged insulation/slipped-off heat shrink, make sure the pins aren't folded over in the adapter plugs, and make sure you didn't pinch a wire when you bolted the radio back in. If the fuse is good, and you test from the yellow wire in the head unit plug to ground, and you should see around 12v whether the key is on or off.

 

The only other thing I see that could take out all the amps at once is the turn-on signal from the head unit, the one you mention in your second post. It should be blue/white coming out of the head unit. Confirm that this connects to the light green/red wire in the harness, and confirm that it tests at +12v when the head unit is trying to play music. If that checks out, I would try and track down the relay for the front speakers to confirm that it clicks when the radio turns on and off, or find the rear amp and verify that it's getting signal to the appropriate pin. 

 

The circuit diagram for the Bose audio system is on EL-145 of the '99 manual (download it from Nicoclub if you haven't yet).

[meatwad]

Fixed!

 

Turns out I’m just stupid. Slartibartfast had the correct solution with the RCA plugs. I was confused because the stereo I set up before did not use them (despite having a factory amp) and they are not colour coordinated to the proper female ports on the headunit. I plugged them into the RL, FL, RR, and RL ports then used the balance/fader while playing music to determine which plug corresponds with which port since it isn’t labelled. 
 

Often times the correct solution is the most simple or easiest overlooked…

 

Thank you Slarti!

[CamperDan]

18 hours ago, meatwad said:

Fixed!

 

Turns out I’m just stupid. Slartibartfast had the correct solution with the RCA plugs. I was confused because the stereo I set up before did not use them (despite having a factory amp) and they are not colour coordinated to the proper female ports on the headunit. I plugged them into the RL, FL, RR, and RL ports then used the balance/fader while playing music to determine which plug corresponds with which port since it isn’t labelled. 
 

Often times the correct solution is the most simple or easiest overlooked…

 

Thank you Slarti!

That's so awesome, basic trouble shooting for the win. I always say when in doubt look again. Glad you you were able to figure this out and now you can enjoy having music in your R50 once again.

 

Chris.

[Slartibartfast]

Nice when it's the simple fix! Good thinking using the fader to work out which output was which.

[EricCR]

I just installed an aftermarket Sony stereo on my 2003 and I have the same issue, i.e. the stereo powers on and works perfectly but there's no sound. I used a harness adapter with RCA (pre-out)

 

According to the service manual (EL section), the BOSE amp only powers the rear speakers. The fronts are driven straight from the head unit. Is that true?

 

I'm checking to see if I wired the amp remote properly, but shouldn't I be getting audio from the front speakers even with the factory amp off?

 

Is the amp also powering the front speakers through this "audio amp relay" circuit?

 

Edited November 21 by EricCR

[hawairish]

The front door speakers have integrated amps, so there are essentially 3 amps for the BOSE system: front LH, front RH, rear LH+RH.

The front amps don't use the remote signal directly; the remote signal triggers the amp relay, and the power signal through the relay powers them (pin 4 on the front door units).  The rear amp uses the remote signal like a conventional amp since it has a dedicated power source...which is also the same power source going through the amp relay.

 

The battery power (always on) going to pin 6 on the factory headunit is the same source that powers the rear amp directly, and also is the power that goes through the amp relay to power the front amps.

 

The remote signal is pin 12; it goes directly to the rear amp (pin 9) and to the amp relay.  

 

If you hooked up the remote line from the new headunit to the factory wire (pin 12, light green w/ red stripe), it should turn on all amps.  The signal would need to be 12v.  If that's good and the rear amp isn't turning on, then it could be the fuse on the Battery (fuse #4 under the dash, 15A).  Does the radio retain it's settings after it's powered off?

[EricCR]

Thanks, man! It was the amp remote signal. I was using the wrong wire from the adapter harness (instructions that came with it are worthless so I struggled a bit, should've gone with common sense instead).

 

Anyway, it's all good now, EXCEPT for one detail: Apparently these Bose amps expect at least 4V coming from the pre amp outputs. The Sony I bought (XAV-AX4000) has 2V so volume is a tad low. You have to really crank it up (volume bar goes from 0-50 and under 35 it's inaudible unless it's very quiet outside). The max volume is just on the edge of what's comfortable so I'm not too upset, but if the audio source is quiet you'll be struggling.

 

I didn't research this beforehand. I don't blame myself as it's something too specific and would've never stumbled upon that unless looking for it, but there you go, in case someone else is thinking using the factory amp with an aftermarket head unit: don't skimp on preamp voltage.

[hawairish]

Correct, you need some sort of line level adjustment to get the volume up on the BOSE amps. I used to run a Scosche OEA4, but this PAC ROEM-NIS2 unit has faired much better: https://www.crutchfield.com/p_541NIS2/PAC-ROEM-NIS2-Wiring-Interface.html?tp=3486

Edited November 23 by hawairish

[EricCR]

I almost bought the PAC line output converter but thought that using the preamp outputs was a more elegant and correct solution. It's just that voltage needs to be a tad higher since you can't play with amp gain. As far as I've read these amps can't be adjusted.

 

The plan is to eventually replace the whole factory setup so for now this is good enough.

[R50JR]

16 hours ago, EricCR said:

I almost bought the PAC line output converter but thought that using the preamp outputs was a more elegant and correct solution. It's just that voltage needs to be a tad higher since you can't play with amp gain. As far as I've read these amps can't be adjusted.

 

The plan is to eventually replace the whole factory setup so for now this is good enough.

 

Like Hawairish, I'm also using the PAC converter and it has been good for several years. I also have the PAC steering wheel remote module. That one is decent. It works perfectly when first programmed and the vehicle is off, but some buttons on the steering wheel stop working once the vehicle is turned on. I have no idea what it is, so I just live with intermittent functionality. 

[EricCR]

That's good info on the PAC steering wheel module, if it's glitchy I might skip it. I also had that planned but I honestly didn't use the steering wheel controls that much, in any car. I'm a perfectionist and I hate having things in the car that don't work so that's my only motivation but I've always found easier to just reach out and use the head unit controls instead.

 

EDIT: This is how it ended up looking BTW:

 

Edited November 25 by EricCR