[Ray Green]

It's Sugar's '02 GC Sport with 3.3L. With the engine running we hear a humming noise, something like a background noise in a radio. We've shut everything off of course and tried to pinpoint it but with no luck. It seems to be telegraphing all around the body. I did open the hood and it's not obviously coming from that area. It just started this yesterday.

 

[ImperialCrown]

Does it change loudness or pitch with any input from you? Have you tried removing the serpentine belt? Exhaust? Fuel pump?

 

[Ray Green]

Does it change loudness or pitch with any input from you? Have you tried removing the serpentine belt? Exhaust? Fuel pump?

I've done nothing but listen so far. The serp and tensioner are only about 6 months old. The fuel pump could be a possibility. I did remove the cap thinking vacuum build-up and it made no difference. I didn't listen into the tank though. Thank you for the guidance.

This probably has nothing to do with this but maybe .... the radio volume doesn't work very well and I spent a lot of time pushing, spinning, twisting, wiggling, etc. the knob while my wife was in stores. I finally got it where we could move the knob, hear sound for a few seconds, then nothing. It was after all that when this humming noise appeared. As I said, with everything electric off except engine, it's still there and doesn't sound like it's coming from the speakers. With engine off and key on, it's quiet.

 

[Varkguy]

If you have the premium sound system you could try removing 15 amp fuse #14 in the IPM to eliminate any possibility the radio is the culprit. It powers the speaker relay and is the B+ power source to the radio. Just be aware it may effect other systems as it is also one power source to the front control module.

 

[Ray Green]

Used the van quite a bit today and heard nothing. Got me paranoid about the fuel pump now. Sugar has a 400 mile trip planned for October. Being 12 years old, don't know the history, and 106k miles, I may just replace it as preventive medicine. They all fail sometime, right?

Varkguy, it's a cassette radio and below it is a 4 cd changer. I'm in hopes Crutchfield will have a good "will-fit" replacement radio as we need one.