air conditioning heater problem

[buckneked7719]

i have a 92 mustang 5.0 the airconditioner/heater blows out of the defroster vent when you step on the gas while cruising. when you let off and maintaina steady speed the air comes out of the dash vents any help would be appreciated its very annoying

[gtnby2]

Originally Posted by buckneked7719

i have a 92 mustang 5.0 the airconditioner/heater blows out of the defroster vent when you step on the gas while cruising. when you let off and maintaina steady speed the air comes out of the dash vents any help would be appreciated its very annoying

First question, can you switch between defrost and vents with the climate control knob and it works? if yes, the vacuum lines are hooked up, it maybe that the vac line comeing from under the hood is plugged or cracked. If not, open the glove box and pull in on both sides to release the tabs (the tabs keep it from falling to the floor). when you do, you can see behind the glove box is a vacuum bank that controls the fuctions and fresh air intake. check the lines (CAREFULLY) to see if one is off or damaged. I had a similar problem in my 91 when a line came off and I only had defrost. if all that is in good shape I'm stumped too.