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So I would try with what you have, as you have to license the PCM with what’s on there no matter what. If neither of those work then I would do the upgrade as necessary but no reason to spend extra money up front if you don’t have to!
you can get the OS from the HP tuners tune depot or I can send you either the original 12212156 one I had before swapping over everything from-my suburban or my current file!
So for using a pressure sensor you will use serial cycling to have it trigger off of the pressure in the A/C system. Analog works with the switch which is either on or off with the A/C
the 99-00 trucks are a little different so you need to be more mindful with the configurations if you upgrade and make sure everything is moved over, such as the charging terminal information as they only use 1 terminal and not 2 like the 01 up trucks. The second link covers that by @1FastBrick and is really good information!
Also, from what I have read, should the type fitted of the A/C be changed from analog cycling to Analog? or serial cycling? I have a stock tune file from a 2002 camaro with the 12212156 and it is set to analog.
Thanks
Also, since you have the 12212156 OS, you can verify if your VIN is accepted by HP Tuners and viewed as by using the VIN wizard and see if it gives you an error saying its a corrupt or invalid/OS pair match. While this is mostly only a concern for people who live in California, I wanted to keep mine matching the vehicle if it all possible just in case. Luckily I was able to even though it does not matter where i live, but just something to check before you burn the new OS to your PCM, that way if you can keep the VIN matching then why not
I can confirm this works for my 2000 6.0 with the 5612 OS. I ended up pulling the A/C sensor wiring from an 04 and the sensor itself, screwed on, and pinned it into the computer. Got the two wires from the fan harness plugged in. Wrote the file and it works perfectly. I have my temps set a little lower than yours, but I tow more than average and wanted them on sooner.
I did not have to use the newer software either.
I removed the Red 33 wire and the Red 11 wire, which were the old A/C recirc command, and the other is the switch wire from the A/C switch. Then I remembered I don’t have any spare pins for the computer, so I cut those and used them for the fan wires. I am never selling the truck, so I don’t mind having them cut.
My brother and I will be doing this on his 01 8.1 and doing a video on it. I’ll be sure to link it here for anyone else who had problems with this so they can get it done!
Hey guys. Little more of an update. Crazy Texas weather recently. Yesterday and today its been 70+ here in Central Texas. Fans have been cycling fine still. But, sitting idling, I am getting warm air out of the a/c in the front. But I am getting cold a/c in the rear. I haven't hooked a set of gauges up to it yet. I will next week.
It seems the fans are cycling with the coolant temps, and it is cycling with the a/c pressures. But, it isn't as cold as it used to be. When I had switches for the fans, if I was idling, I had the fans on all the time. Now, they are cycling with pressures, and it just isn't blowing as cold. When I am driving down the highway, I can get cold a/c.
I've attached my settings below. Any thoughts?
You all have certainly been having some crazy weather down there! Hopefully everything is alright and you and your family are doing good. As far as your truck goes, I would definitely look over your settings and make sure that under the A/C you have the Recirculation parameter set for "Fan #2" and not "AC Recirc" as well as to make sure that your Freon levels are within spec.
Below are the settings for a 2005 Crew Cab pulled directly from the truck. The pressure settings shown are what I originally tried running on my suburban, but when I used these settings here in Maryland i was getting frost coming out of my vents because it was getting to cold so i adjusted them to where they are at currently.
These settings are from when I sent the PCM for my 04 2500HD crew cab off to have the electric fans turned on. This was a little bit before I purchased HP tuners and this is what the tuner set them to. These settings worked really well for my truck, but I changed them because my fan was going to high as soon as the A/C would come on because the same pressures were used for both
These are the settings my 04 2500HD crew cab are set at currently
Hopefully that helps! I think for the first few days i ended up driving around with my laptop and hp tuners to keep an eye on everything and make adjustments to get it right where i wanted it to be!
I have adjusted the low speed enable to 215 and the low speed disable to 150 instead of 190. I can’t get too accurate of a setting because of the fluctuations in the ambient temperature. The rear being ice cold vs the front leads me to believe it is a front hvac problem, not an efans problem. Kinda coincidence, but I have had recirc door problems for a while. So I am going to go through the hvac to make sure everything is working alright. And yes, it is set to #2 fan and not recirc door. Need to get a set of gauges on it to double check pressures.
If the rear is cold and the front is warm I would think you are right in leaning towards a blend door or actuator issue. Do you have a tech 2 or access to one or perhaps a vxdiag nano with the tech2Win software? I bought mine off amazon in January of last year and it allows you to test the actuators to help determine which ones, if any, are faulty so your not shooting in the dark trying to figure out which of the handful of actuators could be having an issue. I originally bought it so i could do the crank relearn on my suburban before I bought hp tuners, but it has a lot of different functions that are really helpful.
02-06-2021, 06:15 PM
