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EMRSR, Master Certified Service Manager
Category: Ford
Satisfied Customers: 3010
Experience:  20 years with Ford, Master Certified
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96 ranger: vacuum leak somewhere under the

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i have a 96 ranger 3.0. I have a vacuum leak somewhere under the dash which doesnt allow the ac to be switched on or the air to flow from any where except the defrost. I can here a sucking noise down near the gas pedle area. I checked the switches or doors whatever you call them, those metal canisters that have vac lines on them. There is no vac at all to those. when i push them by hand the air cycles to the other vents and the ac goes on. Where is my leak? I cant feel it and i dont know where the ac hose actually enters from the engine compartment.

The fact that you have no vacuum in the cab...more times than not the leak is in the engine compartment. Start by checking that you have vacuum to the reservoir tank and the follow the black line into the cab.



EMRSR and 3 other Ford Specialists are ready to help you
Customer: replied 7 years ago.
somethings not right. this doesnt look at all like my control board. For one, I only have 3 knobs. The left is fan speed, the middle is temperature, and the right is for max ac, ac, off, mix, floor, floor/ defrost, and defrost.. Also all of my vacc line under the dash come together into one spot- a small rubber box behind and under the passenger side airbag. There is a tube running from the back of this, but i cant follow it. Am I missing something? I dont see anything like this in this schematic.
OK, I let look and see if there is a difference between sources and I will get back with you.
Customer: replied 7 years ago.
Digging in the Ford Workshop Manual.
Defrost is the default mode when vacuum is lost coming to the control, that is what is showing here, not the heater controls. Have you gone to the reservoir tank and checked for vacuum at the tank and the hose coming into the cab yet ?
Customer: replied 7 years ago.
i traced the 2 lines running from the reservoir and the one leading to the brakebooster is fine, the other one-BINGO. Somewhere between where it goes under the blower fan to the cab must be bad. I bypassed this and Ive got full control. Thanks alot.
Great work !