Air Compressor Sound when I open door

[Kee Yoker]

Just purchased an RST Z71. I am noticing when I open the door there is a air compressor motor sound that comes from underneath the truck. It almost sounds like it is the motorized Step mechanism but I don't have the auto moving stair steps. Anyone have the same sound? Normal?

[Jglew82]

It's your fuel pump priming. Normal operation. 

[Kee Yoker]

That's a first for me. I would not have guessed that. Fuel pump priming upon opening a door. Thanks Greg

[Mikebtte]

11 minutes ago, Kee Yoker said:

That's a first for me. I would not have guessed that. Fuel pump priming upon opening a door. Thanks Greg

Prolly just don't hear it until the door is open. Cabs are pretty insulated. 

 

Do you have steps that should be coming out when the door opens and they are not working?

[Jglew82]

28 minutes ago, Mikebtte said:

Prolly just don't hear it until the door is open. Cabs are pretty insulated. 

 

Do you have steps that should be coming out when the door opens and they are not working?

It's the fuel pump. In 2017 they added this feature that when you open the door after the vehicle has been sitting, it will prime the fuel system to allow the engine to start quicker. This has carried over to the T1 platform.