I have a 1999 F250 Super Duty Lariat PowerStroke 2 wheel posi - My A/C only blows out the defroster vents - I checked under the hood & on the passenger side there is a little black box that has a vac line tee with hoses - all seem tight - there is a hose connection off of this box that is not being used. Now I have owned this truck for about 4 years & the A/C has always worked this way

Called the dealership & they quoted - 1,100 - 1,300 to tear into the dash & find the problem & any parts would be xtra - well no way can I do that

Taking a trip out west late spring & will need that A/C to work correctly or my wife will B&M the whole way so Please someone anyone HELP

Kind Regards

Sonny

 

You probably have a bad vacuum pump. Its either going to be a bad reservoir, inop pump, or a leak in the lines. Turn your key to on. Do you hear a motor humming besides the fan? Go borrow a vacuum pump from Auto Zone and test the reservoir. You can also test the lines this way and to make sure it isn't an internal problem.