glad this post came back to the top. i just bought my 98 and im stuck on defrost too. headed to the garage now to check the vaccum lines. could a broken line cause any shifting issues? i have another post on here about shifting issues if anyone wants to take a look and see if they have similar issues.

 

it indeed was a broken vacuum line right at the firewall right where the ac lines come thru the firewall on the passenger side. 1 dollar worth of hose from the parts store that fit over the small plastic line that was broken. thanks guys for the advice.

 

Yesterday had my 98.5 Ram 24V air vents get stuck on defrost no matter what vent setting I used.

I fully expected the problem to be a blown fuse, but couldn't find a fuse whose description indicated an air vent function.

Found this forum and multiple messages explaining this kind of failure. Popped the hood and there it was, the thin vacuum line leading to the "90-degree turn/check valve" had dropped down to touch the exhaust manifold and melted.

The reason I'm posting here is to describe my fix for y'all ... I discovered the dodge vacuum line tube is a very nice press fit inside some thin "drip irrigation" line/hose I had in the shop. used about 2 inches of this hose, then wrapped the whole shebang with electrical tape. Now the vents work properly.

Thanks to all of you over the years that have discussed this problem and its fixes!

dumdum

 

Isn't the drip irrigation hose porous? (I.E. it will be a vacuum leak?)

Welcome to DF!

 

So glad i saw this, I was in the middle of changing spark plugs lastnight and when i was doing the last to plugs in the back on the passenger side i bumped this cheap looking plastic thing which turns out to be the vacuum check valve and the plastic hose that goes from the check valve into the cab broke in half. So now i got wild vents. I also had wild vents before but no where near as bad as i do now after breaking that.

 

Isn't the drip irrigation hose porous? (I.E. it will be a vacuum leak?)

Welcome to DF!

Thanks for the welcome HeyYou!

Sorry I wasn't clear with my description of the hose I used to fix my "wild vent".

This hose is what is used to connect a filtered water source with specific "drip emitters" that allow just a few drops of water per minute at the base of a plant. They sell emitters that drip at different rates, plus "tees" and "elbows" to allow a number of plants to be watered from the same source. This hose is flexible plastic (vinyl or PVC?) tubing with "about" a 3mm (1/8 inch) I.D. and "about" 1/4 inch O.D. and doesn't leak by itself.

dumdum

 

Ah, cool.

I do like simple fixes.

 

Feet freezing face on fire was best description I'd seen for this problem. Popped the hood to locate the vacuum line connections - and there was the problem. Vac line had dropped onto the turbo and melted off. So, $3 worth of vac line later, I have heat where I want it.
Will update later but hoping that this will solve my chronic issue with Cruise Control. Speed creeps up from setting until I reset it anywhere from 2 to 20 times.
1997 ram 2500 5.9L

 

The vac line also breaks off at the cruise control actuator under the battery. To solve the problem of cracked or melted vac lines use silicone vac line.

 

My 1st post, just bought a 96 Ram 1500, has wild vents, and vent control switch acting flaky as well, have to wiggle it, is it common for those to go bad?