Hello..I have a '99 ram with the 5.9L. The A/C works fine most of the time, but sometimes during braking, it begins to blow hot air. I then have to turn it off for a few seconds, then turn it back on to get it to blow cold again. Any suggestions would be greatly appreciated!

 

Definitely a vacuum leak somewhere. Look for a broken plastic hose under the hood between the engine and the firewall. It'll be real small in diameter.

 

yea.. sounds liek a vacume leak .. your vacume isnt strong enough to hold the blender door in place.. happend to me.. if your truck is a 4X4 then check the hard lines that run from your tcase to your CAD on your front axle.. they are two small hard lines that look like brake lines.. thats where my leak was..

you could do a vacume test and see what your vacume is.. should be 18 inchs of vacume at idle

 

Thanks for the replies. I'll check the lines and keep you posted.

 

Hey, while your poking around in vacuum lines..... Look and see where the green hard line goes near your distributor... please?