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Is this an actuator problem? #3062283
07/25/22 05:48 AM
07/25/22 05:48 AM
Joined: Sep 2003
Posts: 6,847
Missouri
StrokerPost Offline OP
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Missouri
98 Ram truck has an issue with the ac system, when vacuum drops when accelerating up a hill for instance, the cold air in my face drops out and I get what feels like room temp air, possibly from the defrost vents, then comes back on cold in my face when I back out of gas. My actuators, and I think there are three of them, are the vacuum type not electric. Can anyone tell me by the description I gave which actuator it is and the location, or if it's an actuator problem at all, maybe a broken vacuum line somewhere? Thanks for any input.

Re: Is this an actuator problem? [Re: StrokerPost] #3062284
07/25/22 05:51 AM
07/25/22 05:51 AM
Joined: Nov 2003
Posts: 10,228
Colleyville
3hundred Offline
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Colleyville
It's been a very long time since I was up on this, but if memory serves there was a check valve known to fail on occasion. Neither of mine ever failed so no firsthand experience.


'68 Fury Convertible
'69 300 Convertible
'15 Durango 5.7 Hemi
'16 300 S Hemi
Re: Is this an actuator problem? [Re: 3hundred] #3062429
07/25/22 02:01 PM
07/25/22 02:01 PM
Joined: Sep 2003
Posts: 19,624
north of coder
moparx Offline
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north of coder
as i have had several early caravans, that problem surfaced on them as well.
it was in the control, plus a check valve.
i know you don't have a caravan, but are experiencing the same problem with a vacuum control as i did.
you may find something if you pull the control from the dash and check out the back side of it carefully, as well as the connecting hose assembly.
just my experience with the same problem, although on a different vehicle. actually, several in the 85-90 something year range.
beer

Re: Is this an actuator problem? [Re: moparx] #3062606
07/26/22 06:40 AM
07/26/22 06:40 AM
Joined: Jan 2021
Posts: 1,012
rust belt
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Moparite Offline
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rust belt
You have two check valves, one right out the intake and another up by where the vac line goes into the cab) You can get replacements from napa.
https://www.napaonline.com/en/p/NDP7301349

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Re: Is this an actuator problem? [Re: Moparite] #3062620
07/26/22 08:26 AM
07/26/22 08:26 AM
Joined: Jan 2006
Posts: 8,162
USA
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360view Offline
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There was a TSB in the late 1990s to remove the factory vacuum check valve and replace it with a little “vacuum tank check valve combination”

Re: Is this an actuator problem? [Re: StrokerPost] #3062808
07/26/22 05:47 PM
07/26/22 05:47 PM
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Posts: 3,123
N.W. Florida
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Fat_Mike Offline
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N.W. Florida
I had the blend door go bad on my 2001 (common issue), although your description sounds different than what I experienced.
I could hear an audible "thump" under the dash and would get an immediate blast of heat out of the vents.
Just something to consider as you're diagnosing yours...

Re: Is this an actuator problem? [Re: Fat_Mike] #3062902
07/27/22 07:01 AM
07/27/22 07:01 AM
Joined: Jan 2021
Posts: 1,012
rust belt
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Moparite Offline
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Quote
There was a TSB in the late 1990s to remove the factory vacuum check valve and replace it with a little “vacuum tank check valve combination”

There was a tsb (tsb 24-01-96) about the early second gens because they didn't have the second check valve but never hear of this one.

Re: Is this an actuator problem? [Re: Moparite] #3063328
07/28/22 02:44 PM
07/28/22 02:44 PM
Joined: Sep 2003
Posts: 6,847
Missouri
StrokerPost Offline OP
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Thanks guys for your thoughts, I will begin to investigate. Is it possible at this late date to look up any TSBs anywhere?







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