a/c is blowing thru defroster, vacuum pump is running but there is a small tip at side of pump with no hose on it and it is pulling air in , trying to find out if this is a fail safe for the pump, I have manual locking hubs, 2000 f350
JA: Do the vents feel cold? Is there a coolant
Customer: yes cold air, no leaks, vacuum pump is vibrating never heard it before
JA: What is the model of your '00 Ford?
Customer: 2000 , f350 S-Duty, 7.3 diesel
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: yes , I will fix my self, just trouble shooting , just happened friday
JA: Anything else you think the mechanic should know?
Customer: the vacuum tank had a small hole in it long time ago, I put some epoxy on it and it has been working , checked it too, no leaks