I'm a first time owner of 97' 5.9 ram 1500. So fair the truck is working out great. I have a issue with my a/c i think. I live is So Cal. When i have the a/c on during a hot day the blower just turns off. Its also happan with just the fan running. i just seems to do this will doing down the highway though. Any help would be appreciated. Also when I get turn off the engine the radatior makes a hissing noise for a few mins. Is this normal?

 

Maybe the speed resistor is going bad.

 

If you have had your A/C on when you shut off your truck and you hear a hissing, yes that is normal, it happened on my '96 and my '01. The blower issue I had on my '96 where it would shut off while going down the highway, I took it to the dealer and they replaced something. I am sure if you talk to a dealer they can tell you what it is and you can fix it yourself. I dont know what they did so I could not tell you how to fix it.