Humming/buzzing noise between bed and rear seats???

Went out to grab something from my truck tonight and when I unlocked it I noticed a weird humming/buzzing noise going on outside of the truck between where the bed connects to the rear of the cab? Sounded like a fan or motor of some sort running and had a high pitch sound to it at first then got a little deeper after about 30 seconds. My truck has also been squeaking over bumps around the area that I just heard that noise. (Dealership thinks that may be the bushing since it’s only form 3k miles on it). Anyone expierence this weird fan running noise? At first I thought it may have been the tailgate light but then put my ear in between the bed and rear door and could hear it was coming from there. Never heard this noise before and have no idea what it could be? Help!

 

Totally normal, happens about 5 hours after you shut it off.

 

The buzzing/humming sound could be the evap system doing its self check.

Key was out of ignition?
Did it last only a minute to 3 tops?
Was it atleast 4hrs after u last drove the truck?

 

Yes to all of those things. I guess I just had good timing to head out there and catch it right on time haha. Thanks for the reassurance guys!

 

Scared me too. Just the gas evap system or whatever

 

Yep, my 06 does it, and our 17 camry too.

It can startle ya the 1st time.

 

I dont have a 3rd gen.... but look around in your owners manual and i bet it addresses the evap/self test

 

It is in the Owners Manual.

 

The evaporation system works by keeping a -7 psi vacuum pulled on the tank at all times when key is off to keep the gas fumes going through the charcoal instead of going to the atmosphere.

 

A pilot’s nightmare- that’s a great way to get water in the fuel, hu?

-MD500

 

If you can see moisture when the sun comes up,
dont take off till you drain those sumps!!