KLAAAR

It is a '97 Ram 2500 4X4, 111,000 miles. This is probably a rather vague question, but could these two problems be related? Maybe a vaccuum leak/ break?

92DuallyCTD

Well, yes...and no. ;-) I would check all fuses and relays first. The two are actually both vacuum-operated, as the A/C utilizes vacuum to operate switching pots for Max A/C, A/C, Vent, Heat, Defrost, etc. And the cruise transducer utilizes vacuum to 'pull' the cable to operate. But I would think if it was a vacuum pump failure/hose problem, you'd also notice no power brake assist, and the BRAKE light should come on(@ less than 8 in of vacuum). So if you still have good power brakes/no light, I'd guess it wouldn't be vacuum source. Still thinking electrical fuse/relayswitches/etc first. Hope that may help, good luck(and keep your cool when cruisin' - DOH!). Sorry bout that, I couldn't resist!

GAmes

This sounds really dumb, but check to see if your horn works. If the horn fuse is blown the A/C compressor won't engage.

Scramblinman

If the A/C works but only blows cold air out of the defrost vents and the cruise control green power indicator illuminates but a speed cannot be set, then the two problems are related in being caused by a vaccum leak. The common spots to develop vacuum leaks are at the cruise control servo under the driver's sdie battery and along the firewall above the exhaust/turbo. I don't know that a leak in these small lines would be enough of a vacuum leak to affect a vacuum brake booster, and in a 1997 it is a moot point anyhow as that was the first year that Dodge began using the hydraboost system that uses hydraulic pressure from the power steering system to increase brake pressure.

92DuallyCTD

Excellent point, Scramblin' !! I somehow didn't catch the 1997 part, and it was plainly stated! I know better than that also...just shows how much attention I pay sometimes... So I am all for your suggestions also, especially the transducer location under the left side battery box. That is exactly where my 97 had the vacuum hose damaged by leaking acid. Thanks for correcting me/reminding me to read a little closer, eh? Have a good one! :-)

ScottN

Sounds like a vacuum leak. Mine busted off underneath the D/S battery. I replaced it with a hose that looks about 1,000 x more resiliant.