Vacuum pump won't stop running...

krcook · #1 (**permalink**) 10-15-2011, 10:28 AM

Changed oil and fuel filters this week and after starting truck to check for leaks, I noticed a "buzzing" sound from drivers side. Sure enough, vacuum pump is running non-stop. Checked the 4 wheel drive with hubs in auto position and it goes into 4-wheel drive no problem; All AC/heater settings works as they are supposed to; So what gives? Do I need a new pump?

H0USE · #2 (**permalink**) 10-17-2011, 10:30 AM

mine is always on too, it's normal

krcook · #3 (**permalink**) 10-17-2011, 04:54 PM

Good to know

I just can't believe I never noticed it before. As much as that thing vibrates, its hard to believe it will last!

noopS · #4 (**permalink**) 10-17-2011, 05:11 PM

i noticed mine was buzzing all the time after i wired up my PIAA lights and i noticed i bumped off a vacuum line that runs to it causing it to run all the time. now i never hear it , check all the lines

krcook · #5 (**permalink**) 10-17-2011, 05:30 PM

I crawled under the truck and traced all the lines this weekend. couldn't find anything wrong; since all the HVAC operates normally and 4wd works, it is providing enough vacuum; just doesn't seem right that it would need to run constantly; once it creates the vacuum, should it hold the vacuum without running until something needs vacuum? and then it would kick on?

sredmyer · #6 (**permalink**) 10-17-2011, 05:40 PM

Mine was doing that a while ago...turned out to be the line that goes under the battery box. The line had gotten a hole worn in it. Once I replaced the line the pump would run until it built up vacumn and then it shuts off.

You can test this by pulling the line off and sticking your finger over the fitting...the pump should shut off fairly quickly.

Steve