Dumb engine whine question.

[Pfuse]

Hey everyone,

***Disclaimer***

I have very limited knowledge of car audio. The extent of my experience has been installing a HU and a portable xm. So, thanks in advance for putting up with my inexperience.

I have a JVC head unit. I have a XM Nexus 50. These are installed in a Kenworth T600.

Since the built in FM transmitter in the Nexus is garbage I decided to hook in directly to the HU through a AUX input. The AUX input required an adapter that went from the CD changer control to a set of RCA outputs. From there I have a RCA to 3.5mm jack adapter.

I get no whine when using the FM transmitter (just other FM interference), CD or regular FM stations. I do get a lot of whine when hooked into the AUX.

Here is my question. If I wanted to do supplemental grounding, where would I start? The adapter, the other RCA outs (like in the pics), or the HU chassis?

Any tips would be greatly appreciated. And please, remember that I am not a car audio guy and will probably need any guidance explained to me like I am 5.

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[ultimate157 5,000+ posts]

It doesn't seem like the HU is to blame here, because everything works fine except the AUX in.

Have you tried another source (iPod, CD player, etc) on the aux in using the 3.5mm jack?

What is the wiring like on the XM unit ?

 

[Pfuse]

I can play the XM two ways over the HU. One is to use the built in FM transmitter and the other is to use the direct connection to the HU (via 3.5 port > 3.5 to RCA wire > RCA to JVC AUX input/cd changer control wire > HU).

I get no engine whine while using the FM transmitter. Just a lot of interference from the other radio stations in the area.

The ONLY time that I get the whine is when it is hooked up through the AUX port.

 

[ultimate157 5,000+ posts]

Have you tried another source (iPod, CD player, etc) on the aux in using the 3.5mm jack?

I also meant to say electrical wiring, not output wiring

 

[Pfuse]

I have not tried another source although I do have my laptop sitting right next to it. I will try it next time I have the laptop in the truck.

XM is powered through the lighter. I will be hard wiring it as soon as all of the issues are worked out.

 

[ultimate157 5,000+ posts]

I would first try the laptop. Make sure the laptop is 100% isolated from the vehicle aside from the 3.5mm cable.

If the noise goes away, then I'm pretty certain your problem is the cigarette lighter power source.

 

[Memphisv-tec428 10+ year member]

Replace your RCA's