Hi Guys,

After I picked my car up from the shop where I had my Z2 installed there was an annoying engine noise. Sounds almost like alternator noise to me, high piched hum that changes with engine RPM. I took it back the next day and they fussed with it for several hours trying "everything" and the noise was gone. They "turned down the gain on the interface box". Now I can't hear the bluetooth or the NAV TBT instructions (they are turned up all the way on the AV/Syatrm Settings screen).

Any one out there had a similar problem and what was the solution?

Thanks in advance.

I had a similar issue with my 05 H2. My problem was defintely the data bus interface, but I discovered this only after spending days of looking for 'ground loops' and trying to isolate the various components to detect the offending piece.

In the end I had to find a happy medium on the gain setting...that sweet spot where the radio still pumps the Bose speakers and I can still hear the OnStar, but could only detect the engine noise if I got down close to the speaker with no music playing.

When I tried to adjust the noise completely out the unit wasn't pushing the output enough for the Bose and I could barely hear OnStar and the door chime.

Do you know what kind of interface they installed? I used a Metra GMOS-04 (recommended by Cruthfield). I know that unit worked in the 07 Vettes, but maybe not 08. Regardless, you may be able to find a happy medium...hopefully, good luck.

I had a similar issue with my 05 H2. My problem was defintely the data bus interface, but I discovered this only after spending days of looking for 'ground loops' and trying to isolate the various components to detect the offending piece.

 

In the end I had to find a happy medium on the gain setting...that sweet spot where the radio still pumps the Bose speakers and I can still hear the OnStar, but could only detect the engine noise if I got down close to the speaker with no music playing.

 

When I tried to adjust the noise completely out the unit wasn't pushing the output enough for the Bose and I could barely hear OnStar and the door chime.

 

Do you know what kind of interface they installed? I used a Metra GMOS-04 (recommended by Cruthfield). I know that unit worked in the 07 Vettes, but maybe not 08. Regardless, you may be able to find a happy medium...hopefully, good luck.

Thanks for the response. We had to find a happy mediun. They found better grounds and that got 90% of the noise out. Now with the gain back up I can hear the NAV directions, buletoohn & onstar.

I don't know what kind of interface they used but they said they have never had a problem with them. I think the main problem was finding a good ground, which is hard to do on a plastic car....

Have a great day