Buzzing sound.

[mattsn]

there is this small (looks and sounds like a compressor ) device between the Right side battery and and the Blower motor on the fire wall. It wont stop buzzing. If i turn my key to the on position ( with all acessories turned off )it just starts buzzing, wont stop. I can even hear it while im running the truck at an idle. I think it is the same noise that I used to always hear when waited for the Glow plug light to go out before starting it. thing is that it would always stop on its own after a few seconds. It has what appears to be an air inlet on the front side and when i put my finger over the end it will stop buzzing. remove my finger it starts again. any ideas. Also not sure if its connected but my fuel milage has recently gone right to crap.

I asked on the other site but no help yet. trying to figure this out before tonight. thanks
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[SINNER]

its your vaccuum pump. check the small lines going to the front hubs first off. you have a leak in your vac. system. it will affect heater controls and the auto locking front hubs. not sure how it would impact your mileage though.

[mattsn]

i dont have auto locking hubs , all manual in my truck. thanks

[PSDPlayer]

You may have a damaged vacuum reservior. Its that big black oval looking think next to the vacuum pump. The pump will continue to run until it hits a certain point. If any dirt got into it, it can tear up the pump and not let it pull a vacuum.

[SINNER]

do you have a valve on your coolant line for the heater box. mine is vacuum operated and real easy to knock off the line. its right above the passenger side valve cover. it does not seem to be a bad pump because it pulls the required vacuum when you put your finger over the pump inlet.

[PSDPlayer]

You could also have cut one of the lines inside the dash as well.

[mattsn]

well its at a dealer now for other issues so ill let them worry bout this one too. thanks