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Dodge Ram Climate Control



  • Im am a new member.

    I read all 187 posts. My prob is kinda like some/most. I have an 02 1500 4.7. My issue is the heater air is cooler on driver side than pass side. Also, my defrost is cooler than use to be. I can change the direction knob and hear the doors and whatever else move. All vents work, dash floor defrost. Just not warm enough on drive side and defrost. I rem a TSB I had fixed back in 02 maybe 03 but, I was thinking it was a fan motor issue. Is there a time frame on a TSB? They worked on outside mirror too. Some clip or something.

    Any suggestions for my problem?
  • I have had this problem with my 1999 1500 Ram. After replacing the control panel in the dash only to find out it had no effect I found the problem rather easily. I borrowed a friends vacuum gauge and found out I had no vacuum pressure under the dash. I found the line feeding the HVAC system under the hood and immediately found the leak. One of the small hard plastic lines coming from the intake had a small crack in it. I spliced it with a piece of rubber vacuum line and it fixed the problem, all for about $1.00. If anyone needs a control panel for this model truck I have one I don't need. Hope this helps.
  • I used the block of wood also until I figured out I had a vacuum leak under the hood. These hard plastic lines get brittle over time and crack. I fixed my problem with a $1 vacuum hose. Hope this helps you out.
  • youtawyoutaw Posts: 1
    Just as quite a few people have posted, my dad's truck is "stuck" in vent mode only. What's weird, is that it will intermittently goto the floor, but for the most part stay on vent. We have tried calling Dodge directly and we were instructed to contact the principle owner of the dealership where my dad has a service record. The owner said he would contact a Regional Service Rep. to see if he could waive the labor cost, but that was over a month ago. A few calls later to his office and still no return phone call. (Of course as we all know now with the economy, nobody is selling vehicles, so the repair shop is where the money is coming in for them...) My dad has a friend who is a fleet division manager and he advised my dad of the TSB:24-004-03. My dad has been told that there are vacuum lines that run this function, but with a diesel, we thought this wasn't the case. We can find the vacuum line that runs the cruise control, but no others.
    Can anybody give us a direction to look to find a solution to this problem? (Other than paying the $1,000.00 FINE to Dodge for their lack of intelligence in using faulty parts and still installing them anyways..?!) Any advice will be appreciated!
  • corkscrewcorkscrew Posts: 254
    Here is a link to tsb 24-004-03:
    Hope this helps
  • ihccgregihccgreg Posts: 3
    I have only dealt with my 99 Ram 1500 gas burner. My best advice would be to continue to pursue the vacuum leak as this is most likely the problem. The line will be a very small hard plastic line that is very brittle if it is like mine. It is probably on the right side of the truck; look along the firewall to find where it enters the cab. The best way to find the leak is to take a vacuum guage and check the line starting at the engine. I also recommend checking the check valve(s) in the line, if these are malfunctioning it may not be holding enough pressure to operate the system. The system also has a vacuum resevoir but that is probably not faulty.
    Before I did anything I would take the vacuum guage and check the pressure at the door actuator under the dash, this will tell you for sure if that is the problem. If it has less than 18-20 inches of vacuum it is most likely the problem. You can splice the small hard plastic lines with the softer rubber lines available at any auto parts store. Be careful when you are searching for the leaky line and don't break or crack any others. I know this sounds like a lot but it's really not hard to do, just a process of elimination. Hope this helps.
  • seandeeseandee Posts: 2
    I am new, I hope somone can help me out.
    The other day I had three things go out at one time, my dome light does not come on when I open the drivers side door (but does when I open the pass.). The seatbelt light wont shut off when the belts are buckled and the ac blower motor does not work. Does anybody have any ideas? I hope I can get some answers befor I go to the dealership please help. Thank you . I have 2004 dodge ram 1500 3.7.
  • arfan66arfan66 Posts: 2
    You probably don't own this truck anymore but I thought I'd share what I found on mine. The blend door electrical motor gets it's position input from the temp control knob on the dash, the circuit that interprets that input is inside the small assembly case with the motor. You can do a simple function check by unscrewing the motor assembly from the bottom of the HVAC unit, next to the center console (3 screws). The inner most screw is a pain but it can be removed with a 90 deg. offset screwdriver. Mark the metal drive shaft with a sharpie. leave the electrical connector plugged in, start the truck and turn on either the A/C or heater. Rotate the temp control knob and watch the drive shaft rotate. It should move slightly at each temp knob detent. If I selected max cold or max hot, the shaft would turn nonstop in the appropriate direction. This is what broke the plastic driveshaft to blend door shaft adapter. This adapter slips off the blend door shaft and you can manually select hot or cold by turning the blend door shaft with a small pair of channel lock pliers. Now if I really wanted to fix this permanently, I'd need a new A/C - heater control panel and a new driveshaft to blend door adapter. I don't think I can find those at my local auto parts store so the manual select method will have to do. In the future, I might adapt a lawn mower throttle cable to work the blend door. Of course, I could always just buy a new truck (I'm thinking Toyota FJ).........

    Hope this helps......
  • The motor connection and shaft from the blend door axle are metal on this model. The biggest problem comes with the plastic connector between the two metal pieces. A metal replacement is available.

    The motor has internal detection circuitry for positioning the blend door and the motor can turn past the "point of no return" if it is run disconnected from the blend door. Most garages will want to replace the motor, but it can be brought back to life if you disassemble and re-index it. It's not difficult to get the system working again.

  • arfan66arfan66 Posts: 2
    Cool. I saved the motor assembly & screws. Now if I could just figure out how to re-index the motor and where to order the adapter I'd be set!

    Thanks for the insight HeaterTreater, I'll keep at it!
  • zara3zara3 Posts: 12
    Thanks, this is the info we've been looking for!
    We've resorted to installing a cable to try and control the heat over the winter, but would love to have the system working again properly~~:)
  • dokkiedokkie Posts: 8
    i have a 2001 dodge 1500 sport 4x4 with the little motor for the middle blend door i think is shot. I got kinda crazy(probably wrecked it) but i took the motor apart it was full of antifreeze from i think the heater core i replaced a few months ago. i have cleaned it and dried it outis there a certain way that these must be reset some how and should i be able to turn the shaft easily when it is sitting on the kitchen table (because i can't turn the shaft without using quite a bit of force)?? And by the way thank you all!! this is one great site i was ready to give up and go to the shop but now i'm on the road again!! ;)
  • The actuator motor assembly is a simple DC motor geared down to turn the blend doors/mode doors/and re-circ door. The motor has 360 degrees of rotation and there is no index position. Once installed, the computer controls the motor and calibrates the movement by driving the motor to the extents of movement and keeping a digital record. No matter how the motor is turned when it is removed, the computer will figure it out and calibrate correctly.

    You can check the motor with a 9V snap connector and a fresh battery. My suggestion is to cut the 9V snap connector out of your son's electric guitar and solve two problems at once...;-) The motor has two terminals and you can touch the wires to the terminal and the motor should turn and reverse when you swap the wires. If the motor is not working with the battery, you may have some luck with soaking just the motor in alcohol and drying and trying again. Nothing to lose. There are four of these motors on the truck and you can use the bad motor to lock mode door 2 in permanent 1/2floor/1/2defrost and use that motor to control the blend door. Cheap, but it will work.

    While you've got it apart you also want to check the different doors to make sure that they are operating properly. Failures on this HVAC system are common with broken control doors. The simple thing to check is the limit pin on each door. This is an extension like the tail on a "Q" that moves between stop points molded into the plenum box. This limits movement of the door and if the pin is broken, force is transferred directly to the doors and they will break. Internet searches may find more information and pictures.

  • dokkiedokkie Posts: 8
    Thank You very Much!!! I just touched a 9v battery to copper ends on the box motor turned and gears all moved freely!! I just priced one out today and they are $200 and thats with my daughters discount (shes a parts person at a dealership). Man thanks again and like I said before this is a GREAT web site with very smart people like U!! :P
  • dokkiedokkie Posts: 8
    Hi again thought my problems were over but i hooked up 9v battery and control motor works take it to truck hook it back up to wires and nothing. turning blend door(middle one controls temp) by hand and everything seems good. any ideas?? And how would i test the wire harness that hooks into the motor?? by the way i have already checked fuses and checked the wires that go to the switch it self they are plugged in properly. its still cold enough here to use heater and i can switch it to cold manually but i just hate having things not work right in my truck.
  • The computer module will run a calibration routine on the actuator motor to "learn" the end points of blend door movement and then it can regulate the position of the blend door by counting commutator clicks between the two end points. It's a cheap way to regulate a DC motor.

    The computer drives the motor to a stall point, remembers the position, then drives the other direction, counting motor revolutions by counting the clicks when the electro-magnetic polarity switches. If the door fails to stall or the distance is measured as being out of range, the computer throws a fail code and shuts the motor down until the next cal routine. If it again detects a failure, it hibernates again, shutting down the motor, and so on.

    One of two things is going on with your system.
    1. The computer got "confused" during the process of connecting/disconnecting the motor. As Bill Gates has taught us all, when you can't figure out the problem...hit the reset button. The system may just be waiting for an auto-calibration.
    2. The blend door is broken and the system will never calibrate correctly since it cannot reach a door stall point and record the extents of movement. The system will stay in an infinite loop of attempting to calibrate, failing, shutting down the motor and wait. The system will run this routine every twenty time the RAM is started.

    So...time for a reboot. If you have the fancy-schmancy Chrysler computer diagnostic tools, it's fairly simple. For the rest of us, you can force a complete system reboot by disconnecting/waiting a minute/reconnecting the main battery. The entire computer system will reboot and you may lose your radio channel program. Say hi to Bill while you're there. I think it is likely that the motor will come back to life and operate properly. We've already determined that the motor is good with the 9V battery, so the computer module is next.

    You probably should also check the limit pin on the blend door drive axle as described in the last post. If the pin is broken, it's likely that the blend door is also broken or in the process of breaking(screwing up the cal routine). Once the pin goes, it's just a matter of time until the door goes. Dodge will want to remove the plenum box to replace the door and this is an expensive repair. There are aftermarket solutions available.
  • luke1633luke1633 Posts: 3
    2001 ram 5.9. the door only works manually,, Any ideas how to fix this cheaply??
  • zara3zara3 Posts: 12
    Hi Heater Treater;
    Your information has been very helpful, we have tried resetting hoping it would auto-calibrate.. and think perhaps that little "Q" shaped bit on the door is broken, so the door goes all the way one way or the other, so its all the way on High or Off when we're are running the heat or the air-conditioning... could you tell me the aftermarket solutions available for this? Because we do not want to pull the dash apart..
  • Yes, if the limit pin is broken, the system will not calibrate and continue in a "death cycle". The door needs to be replaced to resolve the problems.

    This is a discussion only forum and links to off-site information are restricted. You are on your own searching for aftermarket solutions.
  • I purchased a 2005 Quad Cab Ram 2500 5.9 diesel with 52k. I knew when I purchased the truck that the A/C was blowing very cold but would not switch to recirculate. I figured the switch was bad but after reading this, I may have underestimated the problem. How can I troubleshoot this to determine if it is the type of problems discussed in this thread. I get very cold air but at very low velocity. It appears that all other functions work properly except recirculate. My truck does not have adjustable dual zones.

  • dokkiedokkie Posts: 8
    is it possible that the switch on the dash for temp control may be gone?? I have tested with a wire tester and i have power but only to 1 of the 3 wires that conect the switch and the blend door motor is this normal? i don't think the door is broke because i can set the temp with a pair of pliers from cold to warm to hot by turning the shaft that comes out towards the floor (with motor taken off). Also too like a good student i have tried everything u have suggested which includes unhooking the battery so any further advice will be followed and greatly appreciated.
  • Dodge chose to implement a different control scheme for the HVAC system than other Chrysler products and Ford and Chevrolet, so I'll address all the different issues in general so that you can see the commonalities between the fails.

    Most systems use a "digital" control for vent selection and re-circ. By digital, I mean 1/0, open/closed, and this type of control is easily done with vacuum control. The vacuum switch is either on or off, and the door open or closed. This is fine for all the control functions other than the blend door. No one want the fine control of being able to put 90% of the air through the defrost and 10 through the floor and then decide to change it to 73% through the defrost and 27% through the floor, so it's either on or off with no fine control. The blend door is different because you want the control to be able to change the temperature from 73 degrees to 72 degrees and this is accomplished by moving the door slightly to change the mix of air going through the heater core.

    Vacuum control is problematic because you have to connect to the engine intake system, run little tubes to the various functions, use mechanical vacuum switches...and hope it doesn't develop leaks over time. Dodge avoided the vacuum "problems" by using electronic servo motor control for all the HVAC functions. The scheme connects a small DC motor to each of the door axles with control from the central computer. Each motor has two wires(not three) and the computer controls the direction of movement by reversing the voltage polarity on these two lines. The problem is that the computer has to know the point when the door is fully closed or fully open. It finds this point by driving the door to the extent of movement and recording a voltage signal from a stalled motor. Think of it like rolling up a hand cranked window. How do you know when the window is fully up or down. Easy, you can watch the window and stop just in time or turn til you feel resistance to movement and stop. Most of us have better sense than to torque the handle hard after it stops moving, but the computer system in the RAM does not have the same sense. It torques the door HARD every time it checks for the extents of movement and will eventually break the axle connector or the cheap plastic doors used on the RAM. This is the root cause of all the failures on the different control doors. The RAM is worse than the other automobiles we look at because of the decision to use servo motor control for all functions where most trucks use the motors for blend doors only. Once you break a door, the approved Dodge repair process is to disassemble the dash, disconnect the coolant and refrigerant lines, and remove the plenum box. It's fairly simple to open the box and replace the plastic doors with new plastic doors that will also fail over time. The doors are cheap, but the labor to disassemble the truck to get to the door will run in the $1k range. There are aftermarket solutions that avoid the high dollar work.

    So, let's follow the air through the system and look at the different doors that control the flow.
    1. Air enters the system through either an external vent or internal vent(re-circ). This is an either/or choice. If both the external and internal vents are open, air just flows into the external intake and out of the internal intake at highway having a window rolled down all the time. The re-circ door is easy to see if you are having these kinds of symptoms by fully opening the glove box and looking to the upper right. With re-circ off, the door should be pressed against the inside of the grate covering the internal intake port and it should move when you turn re-circ on. If it isn't moving, it is broken and needs to be replaced.

    2. The air taken in in #1 now flows through the evaporator core. If the compressor is running, the air is cooled, if off the effect is neutral. The air is either cooled or ambient depending on the electronic signals to the clutch on the compressor. Air now hits the blend doors which can divert some or all of this air through the heater core. For max AC, you want the compressor on and no air through the heater core and for max heat you want the compressor off and all air diverted through the heater core. The system can change the on/off cycle of the compressor and position of the blend door to regulate temperature between max heat and max AC. This is the only component in the system that regulates the temperature of the air flow. If you are seeing problems with temperature control, the leading suspect is a broken blend door. Dodge also threw another curve into this by designing separate ducts for passenger and driver with some added complexity and two motors for the dual control systems. The plenum box is the same with either dual or single control and a differential between passenger and driver temperatures is a strong indication of blend door breakage.

    3. The conditioned air from the blend door now flows through the Mode 1 door. This door selects between dash vent and defrost/floor. If you have air flow through the dash vents all the time or no flow through the vents all the time, the Mode 1 door is broken. The door can physically break off and lodge in strange positions so it may not be completely black and white, but inability to control the dash vents is a broken Mode 1 door.

    4. The Mode 1 door will either push air out of the vents or allow the air flow to go to the Mode 2 door. This door chooses between the defrost vent and the floor vents. The system is designed to be a little "leaky", so choosing defrost will put most of the flow onto the windshield with a little leakage to the floor and the opposite situation when the door chooses to allow air to the floor. An inability to regulate between defrost and floor is an indication of a broken Mode 2 door.

    All four systems are equally susceptible to failure. Since the computer system is capable of detecting the movement extents of all four systems, it is also capable of throwing codes for a failure of any of the doors. The above describes the symptomatic analysis of the system, but the codes will also show any problems. The best diagnosis is to see a symptom that matches a code. You have to have the special Chrysler computer diagnostic system to read the codes. You may be able to find a shop that will do this for little cost, or maybe borrow a reader from one of the big parts chains. Note that the doors will "bend" before they break and the variation in calibration can throw codes even though the doors are not yet broken. The door may operate OK even with a code, but once you see a code, it's only a matter of time until it breaks.

    I know, I know, waaaaay too much information and complexity. Blame Dodge, not me. Unfortunately, theres more if you go looking for it. The system can be reliably repaired without extensive work and cost.
  • resqtechresqtech Posts: 1
    After reading alot of the reviews I apologize for repeating anything but each of the blower problems seem like they all have a different twist and I called to see how much the controller was for my truck and the dealer gave me a price of $153 that I would hate to spend if not needed. The problem I have with my '05 1500 is that the blower is stuck on the floor with just very little air coming out of the defrost when I choose 3 or 4 on the speed controller. I have no problem with the speed control, I can select any of the speeds. I also have no problem with the temperature control in the heater or the a/c mode, I can choose any selection for temperature. My truck is not dual temperature control and the air flow and temp seems to be the same on the drivers side floor as it is on the passenger side. Something that I did notice about a week before the blower got stuck on the floor was that one time when I started the truck with the controls set where they were when I turned the truck off, the indicator lights on the a/c button and the heated mirrors button flashed 4 times and then went out, those buttons also still work. It just won't blow anywhere other than the floor. Do you think is a controller problem or is it the mode or defroster door(s)? Any help would be greatly appreciated.
  • The actuator motors are simple DC motors geared to turn the door slowly. It's actually rare for the motor to go bad. The more common issue is for the blend door axle to strip or break and the motor will lose it's calibration limits and be shut down by the computer. The motor is good, but the computer can't find a stop point and sends it into hibernation mode.

    Your symptoms are indicative of a Mode door failure and the system can be repaired for less than the dealer wants for a new motor that won't solve the problem anyway. You can search the internet for more information on diagnosing and solving the problem.
  • sk4910sk4910 Posts: 2
    I have a 2006 Dodge Ram 1500 SLT quad cab with a 4.7L engine. Recently my air conditioner gets hot when the trick is idling. Its like the heater kicks on, the air gets hotter than whats outside and very humid to the point of fogging up my windows. The a/c works fine while the truck is moving. The freon level is good, and I changed the radiator fan clutch. There is also a pop sound that comes from the passenger side dash every time I start the truck. The passenger side a/c runs 80 degrees F while the driver side runs 20 degrees cooler. My truck is out of warranty so I was hoping someone has experience this same issue and could point me in the right direction.
  • The popping sound is a clue that there might be problems with the air flow doors in your truck. It appears that you are getting good AC compressor operation and coolant flow, so "hot" and "cold" is getting into the passenger compartment. It sounds like the problem is how the temperature is being regulated by the air flow circuits.

    The RAM has four different electronically controlled doors in the system and most likely your problem will be traced to one or more of these systems failing. The four actuator motors are connected directly to the plastic control doors and it is a common failure for the plastic to break and lose control over the door. Once this happens, the computer system detects a fault in the system and you can get all kinds of strange behavior. Once a failure is detected, the computer shuts down the suspect actuator motor and goes into a state of confusion. The motors themselves are actually fairly robust, but the plastic doors are weak and break.

    Here are the four systems you need to check:
    1. Re-circ door - regulates between internal and external air into the plenum box.
    2. Blend door - diverts some or all of the air flow through the heater core to regulate temperature.
    3. Mode 1 door - controls air flow to dash vents or defrost/floor.
    4. Mode 2 door - when mode 1 diverts the air away from the dash vents, this regulates between 90% defrost and 90% floor.

    The diagnosis is fairly simple. You can read the codes with a special Chrysler computer diagnostic tool. You may be able to get one of the big parts stores to do this for free if they believe that they can sell you something, or go by the dealer and pay for a diagnostic report. The other way is to analyze the symptoms and examine the plenum box. You can easily figure out the problems once the center console and glove box have been pulled. Figure a couple of hours work.

    There are aftermarket solutions for the weak doors and full diagnostic procedures to trace and resolve the problems. The work is well within the skills of most shade tree mechanics and significantly cheaper than the dealer fix.
  • bndckrbndckr Posts: 1
    kcram: I have a 04 dodge 2500 with climate control with somewhat the same problem.

    At first I had a fan problem and had to bang on it to jump start it... finally bought a new fan and replaced it. Still works good.

    Then the A/C would work on driver's side and heat on passenger side. Driving across country in the middle of the summer it was a pain. Finally stopped in Lawrence, KS(?) and the tech told me that he it was the valve system and he worked them until they worked ok. They did and no charge.

    It's Apr 09 and it started doing it again. I would tear into it and do it myself, but I don't have a clue as to where these "valves" are or how to get into them.

    I live in San Diego and the closest dealer to me is in Escondido and really hate to take it there as they ALWAYS try to do the most expensive thing that there is... Which would be the truck computer... no way jose.

    Would appreciate it if some one could give me an idea where these valves are and any little secrets of how to get to them.
  • stanoskistanoski Posts: 76
    Anyone else having this problem?? I have an 2007 RAM 1500 that smells like an old musty towel for about 1 to 2 minutes when the AC is first turned on and then goes away. Same issue since new and in either fresh air or recirulating position. Also does it for 1 to 2 minutes when you turn off the AC and just let the fan run.

    Never had this in my Ford :(

    Anyone can help? Thanks

    Ski in TX
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    You likely have mold from moisture in the system. Turn the AC on recirc and fog your interior with Lysol spray until the system has sucked it all in. Let it run that way for a few minutes... that should kill the mold, but if it was a heavy growth, you may need to do that few times.

    kcram - Pickups/Wagons Host
  • You also need to check that the drain hose coming out of the plenum box and dripping out behind the right front wheel is clear. If the hose is stopped up or not flowing efficiently, it can cause moisture build-up and promote growth of mildew.

    The internal intake port is located behind the glove box in the upper right corner. With the fan running and the system on re-circ, any liquid sprayed into the intake will be pulled through the evaporator core. Don't worry about too much liquid as it will be blocked by the core and drain out the bottom through the hose mentioned above.

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