I got a 01 cummins 4x4 and my heater or air wont work on anything but defrost and my front axle is kind of slow kickin in so i started lookin for vaccum lines be off and i found one but its broke on both ends and cant find where it goes is there where i can find a diagram.

 

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Not sure if I can suggest a website or not but tradebit.com has a great electronic version service manual which you can download in minutes. It's worth a look, inexpensive too.