D3 Noise Issue: LX450

[smug01]

I have a peculiar engine noise issue with my D3 that I was hoping someone might be able to shed some light on.

 

I installed my new D3 in a '97 Lexus LX450 (very similar to the Toyota Landcruiser) using the Crutchfield wiring harness that integrated the unit with the factoty amp. The factory head unit has low power outputs that feed the amp and my understanding is that its output signals are similar to the pre-outs of the D3.

 

Here is the problem. The unit does not have any noise when connected prior to stuffing it into the dash, but once the D3 chassis contacts the metal vehicle frame, the engine noise starts. I checked my ground 3 times and it is a solid connection (soldered) to the Crutchfield Harness that splices to the orifinal OEM stereo ground. It just seems odd that there is no noise issue until the metal of the D3 touched the metal of the vehicle....then all bets are off.

 

In adddtion, I attached the ILL+ wire to dim the display at night. This works to dim the display, but it causes a slight humming (different pitch from the engine whine) through the speakers irregardless if the engine is on or not.

 

So is my ground not adequate or am I missing something? Why would touching the outside metal cause noise? I did the Bypass per the stickies and grounded both the mute and parking break wire to the same harness ground.

 

Thanks,

 

Craig