Weird Noise After Shutting Off Ignition

iknow · August 20, 2009

My father's Silverado, 2004 I think, Regular Cab 4X4 model, has an issue.

After turning off the ignition there's a buzzing noise that seems to come from underneath the truck (driver's side it seems).....it kept buzzing until he disconnected the battery so it wouldn't drain it if he couldn't get it figured out. He and I think maybe the fuel pump?

Turning the truck on and then off again didn't help anything.

Thanks in advance for any help!

Josh

brims · August 20, 2009

Just some thoughts, does he have any kind of air suspension? I know some vehicles let the fans run for a little bit after you turn the vehicle off (these trucks don't seem to do that, but could probably be made to do it somehow).

Hopefully someone with a little more knowledge will chime in.

bill190 · August 20, 2009

On some vehicles, "accessory power" will remain on after you shut off the engine.

You may be able to set this if you have a "personalization" section in your owner's manual. Or read about it and see how long the accessory power would stay on and when it would shut off.

Anyway might want to wait that amount of time (if this is in your owner's manual) and see if the noise stops. That might be a clue. (If it stays on past that point or stops.)

Other than that, maybe drive your vehicle up on a curb, crawl under it, and find where specifically the noise is coming from.

Then if you don't know what it is, maybe post a picture and describe the general location of where it is on the vehicle.

mtm700 · August 21, 2009

Pull the fuel pump relay and see if the noise stops. If so, swap that relay with another and see if it takes care of the issue.

iknow · August 21, 2009

A coworker had a 2002 GMC Z71 that did a similar thing, the buzzing, he said it was his ABS unit....the box that controls the process? But he had a few issues with it, AC, ABS etc....

My dad works with me so he and our electrical engineer went out and pulled the ABS fuse (60 Amp) and it stopped. He said yesterday after work his ABS light came on and when he got home it was buzzing like a giant bee. While I typed the OP he was outside feeling around and found a small black box and it felt like it was making the noise and it was hot.

I can do a video and put it on YouTube tomorrow morning sometime.

Thanks for the help so far guys.

Josh

Indy · August 21, 2009

It's the ABS pump EBCM, a very common issue. There's a guy on Ebay who rebuilds them better than new for $100.00 with a lifetime warranty. I had mine done last year.

ABS Rebuild

brims · August 21, 2009

Forgot about the ABS stuff, it is right there under the driver's seat.

iknow · August 22, 2009

Thanks for the link Indy, it's a little late to show him lol, Inglourious Basterds was pretty good though....will show him, the $100 option is much less than the range the coworker said his mechanic quoted him to fix his.

Thanks again guys,

Josh

mtm700 · August 22, 2009

Never even thought about that. The only ABS issues we see with these are the pump wires corroded to hell. Now I know what to look for if one ever rolls through the shop with this issue, thanks.

Darkanion · August 24, 2009

Just another thought... Has an HID kit been installed on the truck? I've noticed that the ballast (or something) seems to "hum" for a little while, after I turn off the key and kill the lights. The reason I think it's the HID's (on mine at least) is that it seems to change pitch when I turn the lights off..

iknow · August 27, 2009

Just another thought... Has an HID kit been installed on the truck? I've noticed that the ballast (or something) seems to "hum" for a little while, after I turn off the key and kill the lights. The reason I think it's the HID's (on mine at least) is that it seems to change pitch when I turn the lights off..

No, the only thing 'extra' on it is that he had the towing wiring added at the dealer and even that will blow fuses....but that's a total separate issue.

But we have it narrowed down to the ABS module under the truck, driver's side. He's going to remove it and have it repaired sometime eventually, until then, he'll drive without it's fuse in place.

Josh

splat10 · August 28, 2009

But we have it narrowed down to the ABS module under the truck, driver's side. He's going to remove it and have it repaired sometime eventually, until then, he'll drive without it's fuse in place.

Josh

that's what i said 6 years ago