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Topic: Vacuum pump operation?  (Read 800 times) previous topic - next topic

Vacuum pump operation?

With either just the key to the on position (not running), or even with the main engine running, I hear a pump running up front for just a few seconds -- and than maybe 10 seconds later it kicks in again.

I found it coming from this pump. Is that normal, to short cycle like this?
I'm assuming it is to supply vacuum for the dash Heat-A/C vent flaps?

 

Re: Vacuum pump operation?

Reply #1 –
Michael, That is the vacuum pump that supplies vacuum to the AC and Heater dash controls.  If it is cycling often there is probably a leak in a vacuum hose.  Close off the outlet and see if it still cycles, it should not.  Then go looking for aged cracked lines to heater AC controls.
Gary B

Re: Vacuum pump operation?

Reply #2 –
Thanks, Gary. Will do.

Re: Vacuum pump operation?

Reply #3 –
Quote from: geomm –
With either just the key to the on position (not running), or even with the main engine running, I hear a pump running up front for just a few seconds -- and than maybe 10 seconds later it kicks in again.

I found it coming from this pump. Is that normal, to short cycle like this?
I'm assuming it is to supply vacuum for the dash Heat-A/C vent flaps?

 

Our vacuum pump started to cycle on and off. So here is what I came up with.

Yes, it supplies vacuum for vent flaps and the Ford heater/air controls. Your problem is probably in the Ford unit. After spending about an hour troubleshooting, I found the problem in the slider for the temperature. Just move the slider about a quarter inch or so to the right and it should stop the cycling. I posted the cure and found there were a couple of other members with the same symptoms. Heat & Air Vacuum Pump

Cure: just keep the slider slightly to the right or use a tiny piece of plastic or what ever to block the last bit of travel. Might superglue it in place. Let us know if this does the trick.

Pierce
 

Re: Vacuum pump operation?

Reply #4 –
Thanks, Pierce!

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