Something running after truck is turned off

andreej · September 18, 2016

I've got a 2016 Silverado with 5.3, 10,000 miles. tonight I came home and noticed something was running after the truck was turned off and key removed. sounds like a motor or pump or something and after some crawling around it seems to be coming from inside the transmission. Also, some of the dimmable interior lights stay on - around the radio cluster, around the headlight and 4wd selectors and around the window and door lock switches. Additionally the radio/navigation screen is on too (nothing on screen but it gets brighter or dimmer with the dimmer switch).

I gave it 30 minutes and nothing changed so I started pulling some fuses. Pulling one labled TCM got the noise to stop but looking through the window (not opening the door) I can see the lights are still on. I put the fuses back in and drove it around the block and same issue after turning it off. I now have the battery disconnected.

Obviously I'll bring it in Monday but I need to use it tomorrow quite a bit including going somewhere that it will sit for 7 or 8 hours. I guess I just bring a wrench along and disconnect the battery??

Colossus · September 18, 2016

I haven't heard of this issue before. I'll be interested in hearing what the service department says. Hopefully just a re flash of the on-board computers and you'll be good to go. Electrical/electronic issues are the number 1 trouble area of ALL vehicles now a days.

emeryz28 · September 19, 2016

I have noticed that the radio screen and some lights stay on for a few seconds, and I have also heard that "electric motor sound" for about 10 seconds after shutoff, but it always goes away.

BigBadSierra · September 19, 2016

All I've ever heard was the fuel pump system turning off.

scottl1346 · September 20, 2016

i get a odd sound once and awhile it sounds like a small fan running under the dash maybe for the radio or something but it only lasts a few seconds and stops

Bikemobile · September 20, 2016

My 17' has a low hum/pump sound after it is turned off. I have not timed it to see how long it runs though. No battery issues either.

TJay74 · September 20, 2016

I wonder if the transmission is using an electric pump f some sort and the TCM is keeping it running after key off in order to circulate transmission fluid while it is cooling down.

gtptyler · September 20, 2016

Mine does this as well but it is from a fan that will dry out the air conditioning system. The dealer programmed it to come on intermittently when truck is off after I complained of a musty smell at start up. Not sure if it is a TSB or not

andreej · September 21, 2016

Left the battery disconnected for 12 hours and it's been fine since! Still keeping a 10mm wrench with me in case it happens again! Hopefully it was a one time glitch.