[IowaFarmer338]

I have a 2000 PSD, this am when driving I noticed my truck was just not cooling down inside so I checked my airconditioning controls and found out that I only had defrost. I also noticed that my radio had switched to am on its own. I called a local garage and he informed me to look for a vac leak, I couldnt find where my vac hose goes through the firewall. so this afternoon I had to go somewhere, Now I had air, got to where I was going, left my truck running and when I came back out, only had defrost again.....any ideas? sounds electrical to me with the radio changing, but vac also sounds possible.

 

[Going_Going_Gone]

The mix doors in the climate control system are vacuum operated. If you change functions (say A/C to defrost) vacuum operated doors change the path of the air. There can be three reasons for your truck to be acting as it does: a worn out vacuum pump, leaking 4X4 auto hubs, or some major vacuum leak elsewhere. As far as the radio, /ubbthreads/images/graemlins/shrug.gif

 

[IowaFarmer338]

Ok, so how do I diagnose which one is the problem?