Swap 4 speed a/c for 7 speed a/c

[Elcy]

The nuts and bolts of my question:
I have an '18 classic 2500 tradesman w/ the 4 speed a/c blower. How complicated and how much $ would it take to upgrade to a 7 speed?

Full explanation:
I live in Phx, AZ otherwise known as the surface of the sun. The 4 speed a/c isn't so great during the summer. My wife's Grand Cherokee is in the shop for warranty work and I have a '21 1500 classic rental (thank you extended warranty) w/ the 7 speed a/c, and it kicks ass. Radio package and dash controls look identical except the rental has the shift knob, my truck has the column shifter.
If I was crafty, I'd just swap the two a/c units; I guarantee the guy at enterprise would have no idea.

 

[Moparfanatic21]

I honestly don't know but I will say I prefer the 4spd over the 7 in my opinion. I could only assume without have access to wiring diagrams, that just switching the switch should work. But honestly no idea

 

[1SloRam]

It’s an somewhat easy swap. You need the radio bezel with controls and the module to swap out, it’s on passenger side by kick panel I believe.
These are parts required https://www.ramforum.com/threads/20...speed-harness-hvac-module-and-usb-hub.156069/

https://www.ramforum.com/threads/diy-2013-2017-ra3-ra4-8-4-radio-upgrade-hvac-conversion.135601/

 

[Elcy]

It’s an somewhat easy swap. You need the radio bezel with controls and the module to swap out, it’s on passenger side by kick panel I believe.
These are parts required https://www.ramforum.com/threads/20...speed-harness-hvac-module-and-usb-hub.156069/

https://www.ramforum.com/threads/diy-2013-2017-ra3-ra4-8-4-radio-upgrade-hvac-conversion.135601/

Good stuff, Your search-foo it way better than mine. Thanks for the links

 

[indept]

The only difference is more speeds. The highest on each system is the same speed so speed 7 won't cool any better than your present speed 4.

 

[Elcy]

The only difference is more speeds. The highest on each system is the same speed so speed 7 won't cool any better than your present speed 4.

Where are you getting your data from?

There is a definite difference between the velocity and sound volume of the air coming out of the '21 ram 1500 on level 7 than the '18 2500 on level 4. They are both in my driveway right now, I just fired them up and double checked to make sure I wasn't imagining it.

Historically the velocity of the 4 speed a/c has been a gripe by a number of people on this forum including me. I remember how poor it was when I bought it new compared to the '04 suburban I drove prior.

 

[indept]

It must have a different blower motor. The switch just selects s different value of series resistor to lower the speed & the high position doesn't have a resistor, its a direct connection.

 

[1SloRam]

Good stuff, Your search-foo it way better than mine. Thanks for the links

No problem. Once you learn how to use the forum it’s a great help.

 

[62Blazer]

Where are you getting your data from?

There is a definite difference between the velocity and sound volume of the air coming out of the '21 ram 1500 on level 7 than the '18 2500 on level 4. They are both in my driveway right now, I just fired them up and double checked to make sure I wasn't imagining it.

Historically the velocity of the 4 speed a/c has been a gripe by a number of people on this forum including me. I remember how poor it was when I bought it new compared to the '04 suburban I drove prior.

Need to clarify a few things on the operation of A/C. If you are simply talking about going from a controller with 4 fan speeds to a controller with 7 fan speeds and keeping the blower motor the same it will not make a difference. High is high....so the 4 speed set on level 4 and the 7 speed set on level 7 will be exactly the same. It's not like the 7 speed controller will allow you to "turn it up 3 more levels" and make the blower motor run any faster or pump out more air.
I wouldn't be surprised if it seems like the "sound" and volume of air coming out of the vents between the two trucks is different, but again it's not from the fan speed controller. The difference is somewhere in the blower motor itself (bigger motor, bigger fan blades????), ducting size, and possibly even the size/ratings of the overall system in regards to how cold of air it makes. I would be curious to know if the temperature of the air from the vents varies between the trucks.

 

[Elcy]

Need to clarify a few things on the operation of A/C. If you are simply talking about going from a controller with 4 fan speeds to a controller with 7 fan speeds and keeping the blower motor the same it will not make a difference. High is high....so the 4 speed set on level 4 and the 7 speed set on level 7 will be exactly the same. It's not like the 7 speed controller will allow you to "turn it up 3 more levels" and make the blower motor run any faster or pump out more air.
I wouldn't be surprised if it seems like the "sound" and volume of air coming out of the vents between the two trucks is different, but again it's not from the fan speed controller. The difference is somewhere in the blower motor itself (bigger motor, bigger fan blades????), ducting size, and possibly even the size/ratings of the overall system in regards to how cold of air it makes. I would be curious to know if the temperature of the air from the vents varies between the trucks.

If I'm understanding your post correctly, you are saying the 1500 might have a more powerful blower motor and/or different fan and that is why it pushes more air. I can't imagine the ducting is different but who knows. I also understand you're saying only swapping out the 4 speed controller for a 7 speed controller won't change the air velocity on the highest speed.

So, I guess this takes us back to my original question, as to how to put a 7 speed controller (and fan assembly?) into my truck. I'll have to re read the links 1SloRam posted and search more to see if the motor/fan install is mentioned.

As for air temp, The 7 speed seemed cooler, but I concede there are factors possibly affecting the feel: Volume/Velocity of air, age of truck (brand new 1500 w/ 2000 miles vs '18 2500 w/ 20,000 miles). I didn't stick a thermometer into the vents to check, wish I would have.

Unfortunately, have my Kestrel with an anemometer on it to compare the air velocity of the two trucks, and again, its only 'the feel test' but my son and I both had shocked looked on our faces when I turned the a/c to high in the 1500.

Thanks for the input/explination

 

[crash68]

The '18 may be automatically going into recirc mode when turned to the #7 fan speed, my '15 1500 did this even before I did the ATC mod. To check this manually push the recirc mode button to cycle on and off listen for the blower sound to change when at the highest blower speed.

 

[Mpgrimm2]

4 speed or 7 speed is still 0-12v max of fan speed

or if you want to go full RA4 conversion:

- DIY: 2013+ RA3/RA4 8.4" Radio Conversion Upgrade.

INFO - 2013-2017 8.4AN FW Notes (RA4/VP4 NA).


How to Add Automatic Temperature Control (ATC) to a Manual Temperature Control Truck.

How To: Install a 2018 4C (UAQ/UAS) Radio in 2013 - 2017 RAM.




M² Mods.
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