'07 started making a strange noise after returing from a long trip out to Montrose a few weeks ago. I know, I know - it's almost impossible to diagnose noises sound unheard, but this one is new/weird. I'm hoping somebody recognizes this because it happened to them and is quite unique and repeatable. I been wrenchin' a long time and never had this one before, so here goes....

Sounds like a soft electrical hum coming from inside the cab in the driver's area, near or behind dash. It increases in pitch becoming audible between around 12-1600 rpm. It is definitely engine rpm-related, and gets loud enough to hear between those RPMs. It drifts in below 1200 and drifts out (gets softer) above 1600. Not noticeable at all cruising at 1800, but still there. There is two Autometer gauges in the A-pillar, an EGT and boost gauge. It is definitely NOT boost-related, but an electrical hum of some sort. I want to think it is coming from one of those gauges, but I can't tell for sure.

Gauge cluster about to go FUBAR? Dunno...

 

 

The fact that it's rpm related makes me wonder if it's your tachometer

 

is it coming form the speakers? bad ground?

 

possibly something to do with your alternator is my guess .

 

Boost gauge vibrating, some of them do that,

 

Unplug all the gauges. If it stops, go one by one till it comes back.