What controls the Blend Motor?
03-04-2013, 02:35 PM
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What controls the Blend Motor?
99 Ram 2500
Truck has either HOT air, or COLD air. There is no temp adjustment.
I can slowly start turning the temp **** and right about half-way, the blend door will move all the way.
I've changed temp controls and blend motors. No difference.
Compare to another truck, the blend motor basically moves WITH the temp control adjustment instead of all the way one way---or the other.
Anybody know what controls this?
Truck has either HOT air, or COLD air. There is no temp adjustment.
I can slowly start turning the temp **** and right about half-way, the blend door will move all the way.
I've changed temp controls and blend motors. No difference.
Compare to another truck, the blend motor basically moves WITH the temp control adjustment instead of all the way one way---or the other.
Anybody know what controls this?
03-04-2013, 03:53 PM
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The bit on the bottom where the motor attaches to the door is broken. Search heater treater for the second gen trucks and you will find what you need to fix it.
03-04-2013, 04:45 PM
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I guess I need somebody to explain this to me slowly. I simply don't understand what "heater treater" is trying to explain.
I've changed the temp control, changed the blend motor. No change.
The door opens and closes.
There must be something that tells the door when to "stop".
Just wanting to know what that is?
I've changed the temp control, changed the blend motor. No change.
The door opens and closes.
There must be something that tells the door when to "stop".
Just wanting to know what that is?
03-04-2013, 05:32 PM
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I would like to say there is a RVDT (rotary variable differential transformer) involved which seems the most likely but I'm not 100% sure and have never broken one open to see what is inside. RVDT's and LVDT's are commonly used on modern jet aircraft. Their range of operation is about +/-30deg some more but you can understand what happens when the motor doesn't stop and continues to rotate.. confusion.
The heater treater piece for the SECOND GEN truck will almost certainly cure your problem.
The heater treater piece for the SECOND GEN truck will almost certainly cure your problem.
03-09-2013, 10:35 AM
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One thing that you can look at is the blend door coupler on the bottom of the blend door. This is a little plastic addapter that connect the blend door and the blend door motor. It is very common for them to fail. When they fail, they strip out or crack in half. Most common complaint is the blend door rotating to cold when cold is requested then snapping back to hot. I have seen also where they do what you are describing. basically there is so much play in the blend door to motor that when it is in blend mode, the door just flops to one side or the other.
03-09-2013, 10:38 AM
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It is easy to change. When you have your blend door motor out of the way, just pull on the little black **** and it will pop right out. It may require some needle nose pliers. I think dodge sells them for like 15 dollars or something..
Another tip is, I only remove the one easy to access screw on the blend door motor. The other one is a pain as it is really close to the transmission tunnel. I remove the one closest to the passenger door and bend and swing the blend door motor out of the way. Do this at your own risk as You are bending plastic. I was a mechanic at a Dodge dealership for 15 years and have done 100s of these with out any problems.
Another tip is, I only remove the one easy to access screw on the blend door motor. The other one is a pain as it is really close to the transmission tunnel. I remove the one closest to the passenger door and bend and swing the blend door motor out of the way. Do this at your own risk as You are bending plastic. I was a mechanic at a Dodge dealership for 15 years and have done 100s of these with out any problems.
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10-17-2013, 12:43 AM
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Wondering if Redlinear solved the problem with the heat treater fix. I have the same issue with hot or cold and nothing in between. I have installed the heat treater replacement piece and have a solid connection with no play but still have no variation.
10-17-2013, 11:24 AM
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11-16-2013, 09:26 AM
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[QUOTE=infidel;3207688]http:/heatertreater.net/index.htm[/QUOTE
11-16-2013, 09:45 AM
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[QUOTE=johnh;3212025]
yeah link is 404'd dead.
11-18-2013, 01:11 PM
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11-19-2013, 12:04 PM
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Thanks infidel!
For the OP and others. It took some reading but this is the info you want to know:
"The Dodge actuator motor has a full 360 degree rotation capability with no built in limit stops. The internal gears have a slide connector that moves along a variable resistance strip and uses the different resistance readings to gauge the position of the blend door. When the connector breaks, the motor spins past the point where a valid reading can be taken and the computer control “loses it’s mind” and shuts down the motor. The most common observation is a cracked interposer and seemingly non-functional motor."
"The HeaterTreater provides an unbreakable replacement interposer and fully illustrated instructions on how to open the motor case and re-index the motor gears to restore proper operation. Generally the Dealer will recommend a new motor(including another cheap plastic interposer that will break) at a substantial cost. The HeaterTreater will restore functionality that will outlast the truck at a significantly lower price. The replacement component is good to solve a HVAC problem, but also can easily be inserted into a functioning system to avoid the problem occurring in the first place. Contact us for pricing on volume purchases."
Also might be a fix for people who think they need a new heater core and only are getting marginal heat out put as the motor and door get out of wack.
Nate
For the OP and others. It took some reading but this is the info you want to know:
"The Dodge actuator motor has a full 360 degree rotation capability with no built in limit stops. The internal gears have a slide connector that moves along a variable resistance strip and uses the different resistance readings to gauge the position of the blend door. When the connector breaks, the motor spins past the point where a valid reading can be taken and the computer control “loses it’s mind” and shuts down the motor. The most common observation is a cracked interposer and seemingly non-functional motor."
"The HeaterTreater provides an unbreakable replacement interposer and fully illustrated instructions on how to open the motor case and re-index the motor gears to restore proper operation. Generally the Dealer will recommend a new motor(including another cheap plastic interposer that will break) at a substantial cost. The HeaterTreater will restore functionality that will outlast the truck at a significantly lower price. The replacement component is good to solve a HVAC problem, but also can easily be inserted into a functioning system to avoid the problem occurring in the first place. Contact us for pricing on volume purchases."
Also might be a fix for people who think they need a new heater core and only are getting marginal heat out put as the motor and door get out of wack.
Nate
09-22-2015, 06:11 PM
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I know I'm reviving an old thread. See, the search function does work. lol
My truck has been sitting a lot waiting for the needed trans work. I'm finally addressing the trans. On my way to the shop, there was a clunk noise and my a/c starts blowing hot air instantly. I mean really hot air. All setting were the same. I'm thinking this "Heater Treater" thing might be what's needed to fix it. Does anyone have any first hand experience doing this? Am I on the right track?
Dodge Ram '95-'02 - '95 - '02 - Ram - Dodge
My truck has been sitting a lot waiting for the needed trans work. I'm finally addressing the trans. On my way to the shop, there was a clunk noise and my a/c starts blowing hot air instantly. I mean really hot air. All setting were the same. I'm thinking this "Heater Treater" thing might be what's needed to fix it. Does anyone have any first hand experience doing this? Am I on the right track?
Dodge Ram '95-'02 - '95 - '02 - Ram - Dodge