KcRay
Well-Known Member
Oops that's weird I better go fix that screenshot.
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Air conditioning Hack
- Thread starter KcRay
- Start date
Jhill
Ram Guru
****update**** I found out that Pex have unique size and I previously said 1/2" should work. It actually is smaller than 1/2" and another member determined that Pex 3/4" works perfect with 5/8" hose. Sorry for wrong info.
The heater core does not heat the evaporator coil (which is where the "cold" is). The misaligned blend door(s) allows air to feed to both the evaporator and the heater core, which is why the final blended air that blows from the vent is so much warmer than what comes off the evap coil.
I fought blend door issues with my 2002 Jeep Grand Cherokee Overland for more than 10 years. We had the extended service plan, and every time we brought it in to the dealer they had to completely remove the entire dash and replace components from the back. This RAM A/C issue brings up all those nightmares--I suspect any fix FCA has for this will be similarly labor intensive and costly.
I also had a leaking heater core in that Jeep. I would predict that those who run with no coolant to the heater core will develop thermal expansion leaks on their core if it sees any of the cold air from the evap coil or on a cold day and then is hit with 212°F coolant. Placing a slightly open valve in the core feed hose or even an orifice could plug off when the coolant gets dirty, and you're back to a no-flow situation. The clamps are an ingenious way to confirm the blend door issue, but I would not trust them to be a temporary work-around for long.
I fought blend door issues with my 2002 Jeep Grand Cherokee Overland for more than 10 years. We had the extended service plan, and every time we brought it in to the dealer they had to completely remove the entire dash and replace components from the back. This RAM A/C issue brings up all those nightmares--I suspect any fix FCA has for this will be similarly labor intensive and costly.
I also had a leaking heater core in that Jeep. I would predict that those who run with no coolant to the heater core will develop thermal expansion leaks on their core if it sees any of the cold air from the evap coil or on a cold day and then is hit with 212°F coolant. Placing a slightly open valve in the core feed hose or even an orifice could plug off when the coolant gets dirty, and you're back to a no-flow situation. The clamps are an ingenious way to confirm the blend door issue, but I would not trust them to be a temporary work-around for long.
I haven't tried this myself with a thermometer yet, but if you think you have blend door problems could you simply shut off the AC switch on the dash, or unplug the cable from the AC pump so it will not energize (hence no cooling), then drive around with the dash set to the LO temperature setting.
Have the fan on a low setting.
Now measure the air temperature coming from the dash vents after driving for 10 minutes to allow the duct temperature to stabilize (or do this at night so there is no solar residual heat or residual engine heat). In this case I would expect the duct air temp to be very close to the ambient outside air temperature. If it's a lot warmer, then you may may have a blend door issue adding heat. If it's about the same temperature as the outside air, then the heater core isn't adding any heat.
Is this a valid test?
Have the fan on a low setting.
Now measure the air temperature coming from the dash vents after driving for 10 minutes to allow the duct temperature to stabilize (or do this at night so there is no solar residual heat or residual engine heat). In this case I would expect the duct air temp to be very close to the ambient outside air temperature. If it's a lot warmer, then you may may have a blend door issue adding heat. If it's about the same temperature as the outside air, then the heater core isn't adding any heat.
Is this a valid test?
KcRay
Well-Known Member
"Thermal expansion", I believe you are over thinking this. For years autos have had a heater control valve, you move a lever or switch on the dash and the valve opens and closes, cutting off hot coolant flow or letting more hot coolant in. The new computerized systems are not changing the physical attributes of a heater core. This year looks like Ram did away with the inline heater control valve, and is trying and failing to control the heat with blend doors only.
Billet1500 4x4
Ram Guru
Yeah, its unfortunate they made this decision. Even the 2019 DS classic lost it's heater control valve, I had one as a loaner and popped the hood to check it out and it uses the same set-up as my DT Laramie. Blend doors are an unfortunate requirement for dual zone AC, they should have left the control valve in to shut off heat through the core when the AC is put in max cooling.
Billet1500 4x4
Ram Guru
This video is a pretty detailed breakdown on a heater case out of Ram with dual zone ac. If ram has an issue with the linkage setup on the drivers side blend door actuator and the new DT is anything like this, the fix would require disconnecting the heater core. Evacuating the AC system removing the dash and pulling the heater case completely out of the truck. Seems like integrating a heater control valve back into the system would be easier but both are going to be really expensive to have a proper working system. I wouldn't hold my breath on a fix from Ram anytime soon.
Given that complex video above, a hack re-integrating an electronic heater control valve is probably the only feasible all-season aftermarket solution. Beyond my skill set on how to program it, but much simpler than pulling apart the dual zone HVAC box.
Jhill
Ram Guru
Here is an electronic controlled valve with a potentiometer that you can hide under dash or in glove box if Ram won't fix it and you don't want to adjust under hood manual valves.
Thewrangler73
Active Member
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Hey, so I'm just trying to make sure I'm seeing this right. So you just disconnected the hose from the pump, and stuck a valve and a little section of hose between the original hose and the pump? And this ONLY prevents coolant from going to the heater core, it doesn't block anything else?
Billet1500 4x4
Ram Guru
old air products makes something similar but its a 4 port full bypass and bit more costly at 115 dollars. Total BS you have to put something like this on a $55k truck. The engineers at RAM should be hanging their head in shame. In theory you can integrate a valve like this into the circuit for recirc. Recirc door closes, heater control valve closes, air will be as cold as possible. The question is how difficult that would be. Maybe Ram will have a fix soon and its not worth the hassle of full integration.
Jhill
Ram Guru
The coolant flow comes out of a black pipe on water pump with hose that says "out" and travels to heater core port on firewall. Then other hose from other heater core port returns to another port on water pump and hose marked "in". Member KcRay added a valve between the black water pump pipe and the "out" hose to be able to reduce coolant flow. Other members went to Harbor Freight and bought clamps that gently squeeze down "out" hose to reduce flow. I am planning to do this 2 valve setup with a cross hose to not change any pressures and full ability to partial or totally bypass heater core. I wanted to not increase any pressures in case there is any issue with restricting flow. Here are parts I have ordered to do this. If you choose to do this, it is at your own risk and don't cut your factory hoses so you can remove modification at any time.
Attachments
Yeah, I wonder if it isn't just faulty actuators that is the issue, but would be a few hours labor to replace a $16 part.
Jhill
Ram Guru
When building an all new platform vehicle, they should have required engineers to make the heating/cooling ductwork to be service friendly with hatch sections under dash to service such things as blend doors. These types of problems were happening in years past designs so why not give easier access to such areas?....or possibly spend 25 cents on actual metal part that won't fatigue or break or distort like plastic......hmmmmmm
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KcRay
Well-Known Member
That is correct, very simple and works great. 3 weeks in and no problems, just nice cold air conditioning.
Jhill
Ram Guru
KcRay is our trailblazer on being the first to come up with a solution to make a real difference in AC temps. Like I said before, he should be up for his own ticker tape parade or maybe Nobel prize. Fat guys like me everywhere can now cool down on a hot day! His design has been proven by him that it works fine. I am just a little OCD and thought I would complicate design a little by adding cross hose and second valve. At least we have work around solutions to try until authorized fix is developed.
KcRay
Well-Known Member
Sir, you are too kind. Thanks to this forum and the wonderful internet, I can share my back yard mechanics.KcRay is our trailblazer on being the first to come up with a solution to make a real difference in AC temps. Like I said before, he should be up for his own ticker tape parade or maybe Nobel prize. Fat guys like me everywhere can now cool down on a hot day! His design has been proven by him that it works fine. I am just a little OCD and thought I would complicate design a little by adding cross hose and second valve. At least we have work around solutions to try until authorized fix is developed.
Have you put yours together yet?
U
User_3336
Guest
Clamped now for a week. Consistent 40 degree vent temps! (It was 95 two days).
Jhill
Ram Guru
Last of parts just came in so I will be assembling it soon! Hot weather coming next week. I just want you to get the attaboys for trying it first for the rest of us hesitant to try.
GerryS
Active Member
I don't think you have to worry about increasing any pressures. The water pump just has an impeller to move the coolant. If you close off all the ports, the coolant will just spin with the impeller inside the pump. It's similar to a vacuum cleaner, but in reverse. When you plug the hose on a vacuum cleaner, the motor speed increases because there is less load on the motor, but there is no increase of vacuum.
When you first start the engine, there is a big port closed off because the thermostat is closed, and there is no added pressure.
I worked in a water treatment plant that supplied water to the city of Highland Park. They use big water pumps! They would always start the water pumps with the dampers closed until the motor attained full speed, and then opened the dampers. This was done to reduce the startup current on those big motors, but there again was no added pressure.
Gerry
