weird buzzing in dash

[McDuff]

I've got a new noise;

It is almost a buzzer, but not quite, more like an "arrrrrrr". It is also fairly consistent in an on/off kind of way. It sounds for 2-3seconds, then is quiet for about 30seconds, lather/rinse/repeat...

All gauges good, no lights, nothing to indicate trouble, and like I said it isn't an alarm kind of buzz. I would almost say it sounds like a small air compressor, but again, not quite.

Not much info I know, but have no idea where to start.

[cbeierl]

Check out this thread: Weird Buzzing Noise..????

[NeilV]

A diesel pusher has an electric vacume pump similar to an aquarium pump to run all the vacume operated dampers under the dash for the heat, AC, etc. You may have a some vacume leaks causing it to run more often then it should.

[McDuff]

Thanks Guys, that makes perfect sense. And that'll teach me not to post again without doing a Search here first.