I have been looking for a couple days now. Cant find exactly what I'm looking for. I have a 96 and when the truck is under a load, like going up a hill or accelerating at any time, the air vent switches to the defrost vent. Does any one know where the vacuum lines are or run to. I think I have a leak or crack or something somewhere. The truck has 285000+ miles I think its prob just old and cracked but idk where to look as this is my first dodge.

 

There is a sticky somewhere that has a manual in it. If you do not have a manual, I suggest you get something to use. After the purchase of a vehicle, the manual is my second purchase, Every time.

In the manual I am reading testing procedures for your air system. They have it laid out by models and engine size. I think it should hook you right up.

In the future, list engine size, transmission, year, make etc. to help people identify your problem. You will get more accurate information. Yours seems simple enough, with the right info they will be able to help really quick.

 

The factory service manual can be downloaded from the FAQ,DIY section. Do a search for wild vents, the issue is common and has been well covered.

 

+1 on both the posts above.

No matter what you've got to check all the vac lines. You can start at the firewall on passenger side. One is there directly for the HVAC. It then runs to the top of the motor near the intake manifold. Follow the network.

 

I had the vacuum line chaff through on the firewall.
I carefully pulled it out a little, cut it off and used a piece of small diameter rubber fuel hose to splice it back together (a light smear of black silicone adhesive on the outside of the line, and slide the rubber hose on)... then pushed it back so the rubber hose is through the firewall.

 

I am so glad you addressed this issue and I found it when I did. I was accelerating up a hill today and noticed that my A/C cut out. Then when I got off the gas it came back on. It may not be the same type of situation but, this thread came to mind. It will make me look into it a little better.

See, this is exactly why I wanted to belong to this site and invest so much time. If I can find problems before they are major, I am hoping I will have less future issues. Hopefully keeping my vehicle well maintained and fully serviced, it will last longer and run better for me. Thank you. Being pro active beats reactive any time!

 

^That is classic wild vents Preston.

Go over every square inch of vac line to rule that out first.