with the key in the run position , is the vacuum pump supposed to be running and do it stay running while the engine is running or is there a vacuum switch to shut it off. 03 ram

 

the vacume pump is a gear driven pump that only runs when the truck is running. If you hear something running it is probably your lift pump for the fuel system and it should only run when the key is in run

Chris

 

the pump that i am talking about is the one under the hood ,pass. side near the hood hinge. its a black plastic unit about two handfulls big.

 

It is controlled by the pcm. Only runs when it needs to......cruise, ect.

 

what is this pump? Mine is very loud and is now running almost all the time. Very annoying.

 

Its for your cruise and probably have a hole in your line somewhere and that is why it is running all the time.

 

Thanks, I'll have to do some tracing & searching.