Problem with road noise-static

Sounds like a bad ground, or maybe even a alternator acting up, tho ground is more probable.

 

Start checking grounds around the truck, make sure none have snapped, they are pretty easy to spot.

Also was this noise happening before the alt change or after ? You can check the ground to it also. If it happend after the alt was changed either the ground is loose if it's a really cheap alt they are not normally shielded that well either.

 

Where is it grounded through? Wiring harness? I've always grounded to the chassis or even the negative on the battery terminal. Never had any problems doing it that way.

 

Some folks have put conductive grease in the wheel bearings, so that noise generated on the frame can ground out through the tires as you move. Also, not all tires are built out of conductive rubber compounds, so you end up riding around on a huge, insulated static generator. Conductive ground straps hanging from frame to roadway *may* help.

Are you pretty sure it isn't related to injector pumps and the engine control module(s)?

If it were a private vehicle, and I could find a stretch of road where I could safely put the car into Mexican Overdrive, I'd do that, listen for noise, and if still there, shut off the ignition, continuing to coast. If it's related to the engine running, it's likely RF noise generated in the form of either sparks or pulses from the stuff under the hood.

Otherwise, I'm out'a ideas. You could always try disconnecting the antenna lead and see if the noise all goes away. If not, then it's coming in from your power leads. If the noise quits, then something on or in the vehicle is acting like a tiny RF noise generator and your radio is picking it up through the antenna circuit, like any other radio signal.

73

 

Take some old bungy cords and hang them from the frame so they touch the ground, some put the on the steps. See what happens with that.

 

Sounds like a ground loop. needs to be isolated