mine is doing the same stuff but i still cant figure out where my line is leaking, all my connections are good but my AC still blows defrost? whatever.... not like it gets hot in Florida anyway right

 

we did a new power steering pump on mine this weekend and found several places that are not a problem yet but need to be addressed in the very near future maybe my observations will help.
The rubber boot that connects the aluminum nipple on the pump to the hard synflex vac line: severely weather-checked and cracked.
Next, follow the synflex line up to the firewall. right before it hits the firewall there is a plastic check-valve that is in the line with a couple more rubber lines, these rubber lines are also severely weather-checked. Then it hits a tee and goes left and right along the cowl. Check all the other tees along here for missing vacuum caps. Finally it runs down to a vac switch on top of the transfer case. it foes from there and connects to a pair of steel lines that run down onto the crossmember, across to the passenger side frame rail and then up towards the front axle before transitioning back to a synflex line that routes to the 4x4 engagement actuator on the front axle. a leak between the transfer case switch and the front axle generally will only cause the 4x4 not to engage, but a leak anywhere in the system between the vac pump and the transfer case switch will cause all kinds of weird problems.

 

does your cruise still work, 4x4, ect? if all that still works, its very possible it is something in the dash. either the switch itself, or a broken actuator on a blend door. on my 99, i had one of the arms brake off and all it would blow was defrost

good luck

 

thanks ed, i just did a p pump swap so no my cruise doesnt work but ive gone through the dash and nothing is melted or anything. my vaccum pump is leaking oil a little bit so maybe im losing pressure through oil, new oil lines this weekend and well see. plus i can smell coolant which makes me think its a heater coil but nothing is leakin anywhere lots of q's but f**k it, baby runs good!!

 

Right on the money. My A/C started blowing through defroster vents, and although Cruise Control would turn on, it would not engage. Although the vacuum tube was still connected to the vacuum pump, found a badly deteriorated soft rubber connector at a "T" at the firewall. Made a temporary fix with an odd piece of rubber tubing I had laying around and some electrical tape until I can get the proper part!
1999 Dodge Ram 2500 Cummins with 182k.

 

Really thankful I found this thread, ac has been blowing cold out of the driver side defrost vent and the floor vents only. Cruise control light comes on but can't get the truck to engage in cruise control. Have found the vacuum line/hose disconnected from the lower fitting twice in the last few months and just plugged it back in thinking nothing of it, until today. Haven't put it in 4-wheel drive recently to test that. So, my upper fittings on the firewall are badly deteriorated as well as the lower one which is attached to what I am assuming is the vacuum pump. Can anyone guide me to what parts I need to request at the parts counter in case the unknowledgable people are working when I show up? I have located the check valve that I need, but am a little stumped on the vacuum line size I need and what the rubber type fittings are at the bottom and top of this line. Can anyone recommend what I need? Truck is a 99' Dodge Ram 3500 24 valve
4x4 with 298,500 miles. Thanks!!!

 

While I'm sure someone will come along and give the specs for the hose and fittings... The only way to be sure you have successfully gotten the right part from the dingalings at the counter is to walk in there with the fittings. It's not like your truck is using them at the moment.

 

Thanks for your reply. Going to pull all those parts tomorrow. Was worried that the parts place may not have all the stuff in stock. Didn't want to be SOL while I waited for the store to order my parts. Lucky for me good ole electrical tape has been helping for now.

 

Napa, etc. might not have the EXACT match in stock but vacuum hose is pretty standard stuff. Barring anything weird they will have the fittings and hose you need to get back to normal. They might not look the same white plastic vs. black plastic but unless you sweat those differences, you're good.


Cheers!

 

I have cruise control n the 4wheel drive works but it will only blows cold air out of the defrost do u guys think it's in my dash or a leak