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99 dodge ram A/C Vent problem plz help

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Old 07-18-2009, 06:22 PM
mahicks3322 mahicks3322 is offline
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Default 99 dodge ram A/C Vent problem plz help

I have a 1999 dodge ram 1500 4x4 5.2l.
I have the "wild vents" syndrome where my vents at throttle switch to defrost.

I have done the following to locate/fix the problem but have some questions to get me further....

1. checked ALL vacuum lines with a vacuum pump. ALL lines hold vacuum except for the very thin vacuum line that goes through the firewall behind the glove box into the heater core housing area. This line holds vacuum for no appreciable time. Line does not seem to be damaged going into the firewall.

2. Installed the ram TSB fix for "wild vents" A 35mm cannister looking check valve/vacuum reservoir at the line before it enters into the firewall.....This helped the problem and allowed me to accelerate mildly before I lost enough vacuum to switch to defrost. It also recovered a little quicker but did not fix the problem anywhere close to acceptable.

3. disconnected the GREEN vacuum line that goes to fresh air door vacuum controlled pump behind the glove box. (it was the only easily accessible vacuum line I could get to. while I can see/feel the vacuum line coming into the firewall from the engine compartment, I cannot get to it easily to trouble shoot it.) I observed the following..
-While my vacuum tester is connected to the green tube with the ignition switch to on but engine not running, AND the defrost/vent switch on max a/c; I get a quick vacuum loss until about 4" of vacuum, then a pretty good hold for about 30 seconds. Then I lose all vacuum and it switches to defrost.
- With the engine running, I get normal vacuum at idle on the green vacuum line under max a/c, but a loss of vacuum on this line on every other switch setting and it goes to defrost.
-switching the defrost/vent switch while the engine is running to different settings seems sluggish but it does switch.

My question are (sorry for so many):
A. should I expect vacuum hold on the line going into the firewall to the climate control system?
B. How can I test the defrost/vent vacuum switch? I tried to pull off one of the colored connectors, but it seemed like I was going to rip the tubing in half so I stopped. Can I unscrew the two nuts on the back of the switch to disconnect the connector and isolate/test each port? If so, what am I looking for? This step is VERY important to me because it keeps me from ripping my dash apart further if necessary.
C. If my testing of the defrost/vent switch turns out that the vacuum problem is somewhere else, where/how do you recommend I look/test?
D. could my problem be corrected by installing another check valve/vacuum reservoir inline or make-shifting my own much larger vacuum reservoir?

Thank you for your help with this issue. I hope my trouble shooting makes it easier for you to give me an accurate diagnosis.
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  #2  
Old 07-18-2009, 06:26 PM
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I saw another thread about this involving vacuum check valves.
Try a search
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Old 07-18-2009, 07:14 PM
mahicks3322 mahicks3322 is offline
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Quote:
Originally Posted by Oren09 View Post
I saw another thread about this involving vacuum check valves.
Try a search
Thanks for the reply, but I have already done several searches and replaced all check valves. I have identified an issue with no vacuum hold on the line that comes into the firewall for the climate control system. My problem is somewhere else other than the check valves.
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Old 07-18-2009, 08:09 PM
mahicks3322 mahicks3322 is offline
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I have now disconnected the yellow vacuum line from the vacuum actuator and applied a vacuum to this line. It will not hold vacuum. I have then connected my vacuum pump to the actuator and applied vacuum. It will hold vacuum. This has eliminated the possibility of a vacuum actuator leak. I now need to find where the yellow vacuum line goes and trouble shoot it from this point.

Any help would be greatly appreciated!

In the mean time, it looks like I can "engineer" a block of some sort to the end of the stem on the actuator to always allow full air to the dash ducts until I can isolate the problem :-)

Last edited by mahicks3322; 07-18-2009 at 08:13 PM..
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Old 07-18-2009, 08:10 PM
dodgeram2001 dodgeram2001 is offline
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Quote:
Originally Posted by Oren09 View Post
I saw another thread about this involving vacuum check valves.
Try a search
wow new people are catching on DO A SEARCH!
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Old 07-18-2009, 08:55 PM
mahicks3322 mahicks3322 is offline
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Originally Posted by dodgeram2001 View Post
wow new people are catching on DO A SEARCH!
I DID do a search. SEVERAL searches. I have also, in GREAT, SPECIFIC, AND CLEAR AS CAN BE DETAIL; told you what I have done, trouble-shooted and fixed. FYI, Every single search points to a vacuum check valve or the "wild vents" solution (Which is a check valve and a very small vacuum reservoir, which I have also done as per my original post.)
Or a vacuum line broken in the engine compartment, or a vacuum line broken under the battery, or a vacuum line broken to the supply of the CAD 4x4 switch....ALL of which I have clearly trouble shooted and singled out to NOT BE part of the problem.

I may be new to THIS forum, but I do not deserve this kind of treatment from YOU. Why don't you actually read my post (you would clearly see I am not a NOOB and have done my homework) and help me instead of saying "go search?" I know that it is probably a vacuum leak somewhere between the firewall and the actuator switch and I am TRYING to get some first hand experience to this issue and am SUPPLYING detailed information to help someone that is willing to HELP ME trouble shoot the problem so I do not rip the entire dash out only to find out that it is a simple vent switch problem/replacement.

OR if it is not......................... how to; where to; should I go............to fix the problem.

I am glad to help you get your 94th post by rediculing me. I am happy to be of some "assistance" to you...

Last edited by mahicks3322; 07-18-2009 at 09:00 PM..
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Old 07-18-2009, 11:09 PM
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Dude, give it some time. First of all not everyone has logged in a read your post, so not everyone has tried to help you yet. Secondly, slow down, you can't expect your problem to be solved in one day. Remember Rome wasn't built in a day. Third get a Haynes manual it may give you some information that you have overlooked, and fourth, and most importantly, always remember, we are ALL a bunch of smart asses around here, so if you intend to stick around, get ready for ribbing, it's part of life on this forum. I would say something to to be a smart ***, but I'll give you a free pass this time
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Old 07-19-2009, 07:07 AM
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Doesn't the yellow line go to the control switch on the dashboard? Sounds like the switch could be bad or the test you are doing is faulty , because when you pump the vac pump you are sucking air the opposite direction of it's normal flow. The check valves, switch's and other components are designed to flow one way.Try hooking the vac gauge to that yellow line,start the motor and see what vac you have without pumping the vac pump. BTW, if you tested the rest of the vac lines like you tested the yellow one, depending on which end of the hose you were testing, one end you tested right and the other end you were sucking in the wrong direction. The way you did it , would be fine if you were just testing the hose itself for leakage and had the other end of the hose disconnected and blocked off.
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Old 07-19-2009, 10:40 AM
dodgeram2001 dodgeram2001 is offline
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ok mahicks3322 sory dude i was kinda a D*ck but didnt mean it, had a ruff day an just went off on some people an shouldnt do that cause their are alot of good helpful people on here , so im sorry dude an everyone here i gusse i will just go take a drive for a while.
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Old 07-19-2009, 11:10 AM
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No need to apologize to me. I don't think, LOL
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Old 07-19-2009, 11:15 AM
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I am not 100% sure, but i think the Service Manual d/l. (merry christmas thread) includes the routing and diagrams for the vac lines? Also check the control unit itself for vac leaks.
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Old 07-19-2009, 11:53 AM
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you say you installed the vac canister, when you put a check valve or the canister on the right side of the T, all it does is bypass the original check valve on the side of the manifold and rule out a leak in the line going to the cruise. that should fix it but it doesn't work for everyone, like you and me.

i'm replacing an axle seal on my truck and its been down for a week or so because i'm lazy and haven't gotten around to finishing it. while i was under my truck i noticed that i have a vacuum line cluster (4 rubber lines in a harness) that was just sitting on top of the heat shield above the cat (thanks ****ty transmission tech). anyway, i found out that it plugs into the top of the transfer case so i plugged it back in and i am hoping that it is the reason that the wild vent fix didn't work for me. like i said though, i'm lazy and still need to put my front axle back together before i can find out if that was where my vacuum leak was at.

so check out the lines that go to the top of your transfer case.
also, on the driver side floor, to the right of the gas pedal there is a vac cluster with a few lines and there are two vac canister things under there, one with a red and one with a yellow vac line on them. i think the canister things open and close the blend doors. you can see them without removing any of the dash.
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Old 07-19-2009, 04:56 PM
mahicks3322 mahicks3322 is offline
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Quote:
Originally Posted by Ram15002ndGen View Post
Dude, give it some time. First of all not everyone has logged in a read your post, so not everyone has tried to help you yet. Secondly, slow down, you can't expect your problem to be solved in one day. Remember Rome wasn't built in a day. Third get a Haynes manual it may give you some information that you have overlooked, and fourth, and most importantly, always remember, we are ALL a bunch of smart asses around here, so if you intend to stick around, get ready for ribbing, it's part of life on this forum. I would say something to to be a smart ***, but I'll give you a free pass this time
Thanks for the pass. I was not expecting to get a result in an hour or a day. I was just irritated spending hours searching online and digging into my boat truck troubleshooting in the hot florida sun to get told to go and search. I was pissed for good reason but completely out of line. I have apologized to dodgeram2001 and am in a better mood and will play nice from now on. If not, I expect a full hazing or ban from the forum. Thank you all for putting up with my rant!
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Old 07-19-2009, 05:20 PM
mahicks3322 mahicks3322 is offline
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Quote:
Originally Posted by zman17 View Post
Doesn't the yellow line go to the control switch on the dashboard? Sounds like the switch could be bad or the test you are doing is faulty , because when you pump the vac pump you are sucking air the opposite direction of it's normal flow. The check valves, switch's and other components are designed to flow one way.Try hooking the vac gauge to that yellow line,start the motor and see what vac you have without pumping the vac pump. BTW, if you tested the rest of the vac lines like you tested the yellow one, depending on which end of the hose you were testing, one end you tested right and the other end you were sucking in the wrong direction. The way you did it , would be fine if you were just testing the hose itself for leakage and had the other end of the hose disconnected and blocked off.
zman, I checked vacuum by disconnecting the yellow line from the door vacuum switch with the engine running yesterday. I get about 15" of vacuum. When I kill the engine but keep the rest of the test the same, I cannot get this same connection to hold vacuum. I wanted to know if this was normal and if not, that means I have a leak somewhere from that yellow line (which runs from the switch) the switch, to behind the dash, to behind the heater core, to the firewall.
i do understand what you are trying to say, and/but I think I did it right. Then when I got done testing that, I hooked my vacuum pump where the yellow connector went on the door vacuum stswitch, I could get it to hold vacuum and the actuator would pull the door down to regular ac vents and hold it there. That is why I do not think I have a problem at the actuator.

I really think it is going to be at the switch or the lines from the switch to the area behind the glove box. I really want to know how to test the switch to eliminate that dang thing! :-)
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Old 07-19-2009, 05:25 PM
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Quote:
Originally Posted by Sheriff420 View Post
you say you installed the vac canister, when you put a check valve or the canister on the right side of the T, all it does is bypass the original check valve on the side of the manifold and rule out a leak in the line going to the cruise. that should fix it but it doesn't work for everyone, like you and me.

i'm replacing an axle seal on my truck and its been down for a week or so because i'm lazy and haven't gotten around to finishing it. while i was under my truck i noticed that i have a vacuum line cluster (4 rubber lines in a harness) that was just sitting on top of the heat shield above the cat (thanks ****ty transmission tech). anyway, i found out that it plugs into the top of the transfer case so i plugged it back in and i am hoping that it is the reason that the wild vent fix didn't work for me. like i said though, i'm lazy and still need to put my front axle back together before i can find out if that was where my vacuum leak was at.

so check out the lines that go to the top of your transfer case.
also, on the driver side floor, to the right of the gas pedal there is a vac cluster with a few lines and there are two vac canister things under there, one with a red and one with a yellow vac line on them. i think the canister things open and close the blend doors. you can see them without removing any of the dash.
Cool, I will check this. I am not too optimistic though since I held vacuum on ALL individual lines under the hood except for the firewall line that runs to the AC controls. Maybe I tested wrong though so I am going to try this and see! Thanks.
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Old 07-19-2009, 05:35 PM
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If you can't figure out what is going on behind the firewall or inside the dash box, why don't you spend a little time at this link (below) and read through the TSBs for your year truck. You may get some useful information. The 98+ Rams are notorious for vacuum problems, and there is a TSB for it.

http://dodgeram.info/tsb/index.html
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Old 08-17-2011, 01:46 PM
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Default wild vent syndrome

i got it!, vents switch around from ac to heat to defrost, ya just never know what is going to come out. I was wondering if you discovered what caused your problem.

Thanks
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Old 08-17-2011, 01:48 PM
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Check this thread out http://dodgeforum.com/forum/2nd-gen-...ild-vents.html
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Old 08-17-2011, 09:17 PM
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Default 98 ram with different vent problem!

My 98 5.2L ram has a very weird problem with the vents...it's not the wild vent problem that everyone has...mine is this:

My ac blows extremely strong out the driver's side vent. The middle two vents hard have air blowing out of them..the vents on the passenger side are alittle more air flow than the middle but nothing compared to the drivers side vent! It is totally crazy...can anyone tell me what is going on..????
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Old 08-18-2011, 09:04 AM
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Default wild vent syndrome

unbelieveable! first vacuum hose i looked at had the break in it. turns out the grey one that ends up going thru the firewall and in behind the glove box was the culprit.

Thanks to all that participated.
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Old 08-18-2011, 09:04 AM
 
 
 
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