I have a 2004 infiniti g35x with stock bose
I have the metro kit with a Kenwood single din radio (kdc-bt858u)
Originally I installed the 7551 wiring harness with the RCA cables. Everything was working fine but it was quiet at around 10 volume when it should be loud and it was not as loud as it was with the stock radio. I found out about the PAC ROEM-NIS2 and ordered it . Upon installation i found out there are 2 positives for each speaker one for the high and one for the low. I put them together and played the radio and it sounded louder but distorted. Then i tried disconnecting the low + and leaving them hanging and it still sounded distorted. I didn't know what to do so I called a audio place I know and they said they use the 7551 and cut the rca's so thats what i did. after putting all that together no sound came from any speaker and thats where i gave up
I also have a aftermarket amp and 2-12" subs
Can anyone help?
they gave me a price of $60 to just wire it up, but I think if they are using the metro harness then its not going to be as loud as it should be

 

Not sure if you broke something when you combined both outputs. The high is the high-voltage speaker-level outputs, while the low is the low-voltage amplifier-level outputs. Putting them together may have screwed up the radio or the ROEM. The way your wiring should be hooked up is detailed in the radio install sticky: https://g35driver.com/forums/audio-v...urce-list.html

To see if you're still outputting a clean signal, connect a speaker directly to the high-level output from the radio. If you're getting a clean signal from all your channels, the ROEM connected according to the wiring chart in the linked post should work fine for you - it has for hundreds (thousands?) of others.

However, the bose amps in these cars have extremely poor consistency, so even if you've got everything right, there's a chance you've got an amp that just refuses to work with anything aftermarket, and it's a great excuse to upgrade to something better. A $200 4-channel amp running the front speakers and rear deck will be fine.

 

I forgot to add that I put back in the stock radio and the volume is fine.
How would I go about testing the radio if I don't have another speaker?
Would the low-voltage amplifier-level outputs be used when i get a 4-channel amp ?

 

Well, if you hook the high-level signal wire up to an analyzer and check the output vs. the source signal, you don't need a speaker, but that's not really going to help you. You're much better even taking the door apart and running speaker wire from the new radio to the door speaker to test, after unplugging the existing radio harness, of course.

Yes, the low-voltage amplifier-level outputs are used with an amplifier. If you're using an aftermarket amplifier, you don't need the ROEM at all, just a 70-7550 or 70-7551, and even then, you're only using half the harness, since you're using RCAs for the signal, not anything out of the 70-7550 or 70-7551.

 

I can use a power probe. So the voltage on both the radio side and the harness side should have the same steady voltage?
I just remembered I do have a speaker but its not a car speaker . So i wire up the radio to turn it on and try my speaker on each Speaker +/- and it should come out clean? (right rear, left rear, front right, front left)

 

Power probe won't tell you anything about the sound quality, just that you've got a signal, which was already established.

Any speaker should be ok, but something around 4-8 ohm would be best. Just start low on the volume and slowly go up.