2nd Gen Non-Engine/Transmission Dash Vents

[TORQUE THIS]

My vents are stuck in defrost. Selecting AC, floor, dash vents, still stays up by the windshield.

Any ideas?

 

[Deezul1]

With no truck info its hard to say for sure but 96 and older have problems with the vacum pump sucking oil through the seal which contaminates everything in the vacum system and damages it. There is a TSB #720 i believe which gives extended warranty on the vacum system for 7 years unlimited miles and they will replace all damaged parts free. This applies to certain serial # trucks. The default position for the heat A\C is the defrost vents if there is a vacum leak. Also if you have been under the hood for any reason check for vacum lines that have been knocked loose.

 

[chrleb1]

I had this happen to me also. The vacuum line into the cab had gotten blocked somehow. YOu can check by finding the line that goes into that cab and seeing it has vacuum. If it does then take the dash off, take the air control panel loose, and then check for vacuum there. I ran a new line into the cab and it worked perfectly.

 

[TORQUE THIS]

I found it, the line that goes to the vac pump by the vp44 was off. Must have knocked it off while working on the fuel system.