Thank you for the reply.
Fuse 27 powers the vacuum pump under the hood. When you turn the key to run without starting the engine
you should hear the pump run. If it does not, this is the problem with the A/C blowing out the defrost only. It is most likely what blew fuse 27 in the first place. Now that it has totally failed, it is not pulling any current.
The instrument cluster either thinks it is being tested, or has lost it's calibration, either way it will take the dealer scantool to straighten out. May need a new instrument cluster. Be advised that if you try to replace this yourself, it will have to be programmed before it's drivable.
The A/C performance issue is common on your truck. Here is a bulletin Ford has released to address this.
Best of luck
LACK OF A/C COOLING DUE TO DESICCANT MATERIAL CLOGGING THE ORIFICE TUBE
2004-2007 F-Super Duty, F-650, F-750 ISSUE
Some 2004-2007 F-Super Duty, 2004-2005 Excursion, and 2004-2007 F-650/750 vehicles may exhibit a lack of air conditioning (A/C) cooling, due to desiccant material clogging the evaporator core orifice tube. Symptoms may include excessive high side pressures. ACTION
Inspect the orifice tube for desiccant material clogging the tube. This material has been described as being like sand, with a greenish color. If desiccant material is present, refer to the following Service Procedure. If not follow normal diagnostics.
|1. ||Replace the orifice tube. Refer to Workshop Manual (WSM), Section 412-03: Removal And Installation - Evaporator Core Orifice. |
|2. ||Replace the suction accumulator/drier with a revised part. Refer to WSM, Section 412-03: |
Removal And Installation - Suction Accumulator.
|3. ||Replace the compressor. Refer to WSM, Section 412-03: Removal And Installation - Compressor. |
|4. ||Flush the condenser, the lines and the evaporator core. Refer to WSM, Section 412-00: General Procedures - A/C System Flushing. |
IT IS VERY IMPORTANT TO COMPLETELY FLUSH SYSTEM OF ALL MATERIAL, OR ISSUE WILL OCCUR AGAIN.