AC Blows Hot When on Cold Setting and Cold When On Hot Setting

Essentially the voltage is inverted on 05-08 and 09-15 trucks so if you swap the temperature actuator or control from one year range to the other hot will be cold and cold will be hot.

 

Oh interesting. It def was not doing that before I changed the stock headunit and ac temp controls to the Aucar headunit. Wonder if there's a fix

 

Unless there's a way to invert the voltage output of the temperature control on the headunit the only option I know of to correct it would be to put an 09-15 temperature actuator in it.

 

when you say actuator do you mean a new plug in? that is the thing all the wires are connect to that plugs into the headunit?

 

did you ever get it fixed by chance? I have the same headunit

 

No the actuators are the motors that move the doors in the HVAC unit, they are located behind the glovebox.

 

oh I see, thank you for the photo that helps a lot. Good to know I only need to access the glovebox. Will consider this in the future.

 

hey guys, Ive had the AUCAR android 11 with 8/128 memory for 1.5 years now,

anyway i had the exact same issue when i first installed it where i was experiencing hot and cold reversed. thats an easy fix, the AUCAR rep would tell you if you asked him but ill tell you.. there is a hidden pushbutton trick to reverse them..... its software agile and you dont have to rewire anything... you press and hold the defrost button for 5 second and that flips the software state to make your hot cold work correct

just to be clear, its the 3rd button down on the right side of the screen, the button under the temp - button, the button that has the icon that looks kind of like a cloud with rain coming out of it symbol, press and hold for 5 seconds

 

That's awesome! Thank you, I'll give it a shot tomorrow morning just to make sure you mean this one I circled:

 

Not the soft button in the screen. The hard button on the right side bezel. That’s the defrost bottom you push and hold for 5

 

Also. Just so you know. Anytime you turn on the vehicle. The temperature will be where it was last selected. If that was hi. It will reboot and show hi. If that was lo. It will reboot and show lo. If that was say for example 73 degrees is where you last had it before shutting if the vehicle. It will reboot and show 73

but..z the temp will be full hot coming out of the ducts until you change the temp even if it’s just changing it one degree and moving it back. The circuit board isn’t detecting the temp it that was last set at last power off when you reboot it. It shows but the board isn’t responding tonit unless you move the setting then the board reacts to it


I report this to them a while back. But still haven’t seen them fix it. Hopefully others will contact AUCAR and ask them for a fix to be included int he next software patch update they send. There is a guy in this site that always posts the latest software release in a zip file he gets from the AUCAR rep so I always grab that and update form his ongoing AUCAR post Search for it . Save a me from instead having to independently ask the rep myself via whatsapp


The full hot nuisance I’m use to. I just usually bump my bezel hard button temp up and then bump the temp down button to move it back and it then responded to the stetting that was retained since last time I had the car turned on. But wait until boot up is complete before doing that or you’ll have to do it again for it the temperature control circuit board they added to the back of the tablet unit that your trucks temp control harness plugs to to sync to the software setting you had it at. AUCAR chose that board. Attached it to the tablet and then wrote software to drive its circuitry as a solid state stepper resistor to command trucks mode and temp module and simulate the control panel it replaced. They just failed to have ther software they added to the tablet to sync to the board in start up until you make a change to a setting then it syncs. People don’t understand that technically so they aren’t knowing how to complain to get them to fix it and they aren’t going to put priority and listen to just one guy like me. They’ll only fix it if everyone contacts them. So look for that issue. Regardless if you toggle the hit cold or not by the 5 second button trick. The temp isn’t setting to the boot up position and most people don’t notice that because It’s possible that if you leave it reversed. Then it defaults booting full cold regardless of the hot cold setting when the controls are reversed as opposed to full hot when the cold trips are correctly by the 5 second trick to toggle it either way. I’m not sure. Because I didn’t notice this until long after I toggled it because I did it at winter and didn’t mind nor notice the full hot while trying to warm engine and car. Because usually I was trying to command full hot not knowing it was defaulted there But when summer came around and the truck warmed fast. I start burning up before I realised i had to move the selected temp and then back to get it to sync after boot anytime I was like lo or or low temp setting Maybe I’ll toggle my 5 second button back and reverse them and then see if it always comes full cold regardless of setting before you then have to bump the temp to get them to sync


So basically what I’m telling you is that this additional issue I’m mentioning isn’t because you toggle the hot cold direction. I think it’s there already and you haven’t noticed it yet or maybe because it’s winter now and maybe it’s defaulting full hot regardless of which way your hot cold controls are toggled Yours being reversed right now. Mine now normal I’ll try and experiment more when I get home from flying my business jet on the trip I’m on but that’ll be another week. In the meantime if you all can try it. Maybe you’ll see and report it here and then to AUCAR also. It’s stands to reason the the circuit card wouldn’t flop on its default setting when not synced to the software that you have toggled either reversed or normal So I’m willing to bet yours still boots full hot even if you have the engine warm and then select full cold then turn the car back on immediately and look and see if your temp is still set full cold. (Lo). But your heat is still coming out when it boots up Or in your case with it reversed. Set it to full hot which should be commanding full cold But your heat will be coming out full hot. You’ll notice it if the engine is warm already. Since it’s reversed on you and you are starting with a cold engine you probably haven’t noticed this other issue yet. In any given power cycle. Once you change anything once. Whew the it’s mode or hot or cold direction it then stays synced for that entire power cycle and it will respond to any further changes without losing sync It just at power up the board isn’t reading the setting in the software because it doesn’t call to ask for what they were left at. Instead what happens is the board defaults and waits then only reacts and syncs once something is sent to it and something is only currently something only sent when a change input is made. They need to have the software send the settings it retained from the last power off at the moment of boot up without anyone having to change something to initiate a send to the board. They can’t make the board ask. It’s not capable. But they can have a patch fix that says basically he. Software. Once you boot and you pull in the memory of what mode and temperature you were at the last time you powered off. Then send that data like 1 time at like 1 second after completing boot up so the board re syncs to those setting and hold them until you decide to change temp or mode and the softer then sends an entire command to the board for it to match all settings the software is set. The send always contains all settings. Not just the one you change. For example is you just change the vent selector say from floor only to floor and dash vents open…. The entire message is sent to the board for not just vent selector. But for that and for mode and for temp selected even though you don’t touch any other control setting


And sorry about that. I probably over explained it 5 different ways to say the same thing but I just want people to understand how it works How most any software controlled hardware board works You have to send the entire message to them at boot up becaue the board dumped its setting at power down and the tablet software, when it boots it reads a config file that got written to every time you changed a setting and retains all those setting in that file at power down then it reads the config file to resume them at boot up once the program reloads at boot up ….They just forgot to make it send a initiator message of the setting reloaded into the tablet software at boot up to the board without having you need to change a setting for it to send its first send to get it to sync and then hold the board there in that power cycle until a new message is sent again by your changing something. Mode or vent or temp etc the board has memory that doesn’t retain if it loses power when you turn off the card and it isnt capable of asking the tablet software
For its setting it a listen only device that cant retain what it last heard when its powers off. The tablet in the other hand write to a temp config file what your current setting are and it maintains that and rewrite everytime you change something and the. Also sends that to the external board And in boot up it rereads that config file because it’s not lost. And it doesn’t have to be in powered memory. The config file is not affected by power loss. So when the tablet powers up and loads the environmental control page. It reads the config file They just forgot to say hey at power up also send that back to the board even though nobody changed anything to write a new message to the config file causing a send to board message to happen


I’m not a software engineer but I am a engineering test pilot and I know of how oversight in software can cause problems like this because I see it all the time on new aircraft systems

if I was a software guy I’d fix it myself. But I’m not. I don’t code And I really sucked at trying to explain all that. Sorry It was probably painful to read and I do t feel like trimming down. But at least I know you understand it despite my ridiculous attempt at trying to over explain it

Hope that helps

 

Oh, I understand! The actual button with this logo! Yeah, it has the two buttons above it with "temp -", and "temp +"
Thanks!

 

Oh I see. I like the idea of having it return to where it last was but that's no good. The issue I seem to have is I would like the temps turned "off" almost all the time and even when I hit the power button off and everything seems off I will still feel a slight bit of heat in the vents. It's not there usually. If you know of a way to just keep everything off that would be good. I noticed if I try to put the temp somewhere in the middle sometimes it cancels out and will not emanate through the vent but not always the case.


Also, I think I know who your talking about. Do I need to grab the latest update too? I just got mine in December

 

Yeah grab the latest and hopefully if I remember he give instruction on that thread with how to prepare the file into a usb stick. Where to place the file and the directory name. I can’t remember but go find his thread

also. As painful as it might be. You might want to reread my last posting because I was still editing and correcting typos and adding to it when you quoted it. So go check. I may not have fixed everything and may have made it more ridiculously long and over explained. But make sure you reread it incase any info I had caused misleading info before I had a chance to edit it

I really need others to report it to AUCAR to get them to place importance on adding in a patch for this when they next release a update

 

Tell them this. Cut and paste into an email if you have to. Say..

Upon power up. The temperature controller hardware board in the back of the tablet is not synchronized to the last known settings for mode, vents selected and temp setting selected that were last written to the config file prior to last power off and therefore when it is rebooted and the program loads. When the config file is read and restores the settings in the software page. But the tablet isn’t sending those setting back to the board until the user makes a change to something then the board responds to the first change and there after for every change made during that power cycle.

Your software needs to be fixed so that when it boots up and the software loads and reads the last known settings from the previous power cycle it then too need to send those setting out to the board Right now thats not happening and the board seems to be holding a default state when it doesn’t know the resumed settings that were loaded to the software page until it gets its first message which is only happening when a user makes a change to a setting on that page

 

will do! Thanks for your help as well

 

And for what it’s worth. Regarding the memory retention of last known setting from the previous power cycle … It’s probably not a config file. It’s more likely a table that’s part of a json table or some kind of SQL table or some kind of look up table of some kind that is a written to as a file and stored in the non volatile section of the tablets memory so the data needed by the program when it boots and reloads can call to that and import those last known settings. That works. It’s just they need to also imitate the software to send the message containing those setting out to the card without someone having to change any setting to get it to first so that


There. That’s said better now too


I’m not the software coding nerd. They are. But they should get the point with what I suggested to cut and paste earlier using that word for word

and I know enough to know that that is such an easy ask for any software engineer to create a patch and release. It’s not difficult at all if you are a coder to correct this because it’s clearly explained and they just have to apply the proper commands for whatever operating system and language their code is written in to insert the function and setting for that function into the existing program and make sure it performed once the tablet is booted and is finished loading the last known settings. It’s a one time command they need to add at the end of the boot up section of their code. It doesn’t need to be in the continuous looping section of the code because the looping section is where it already knows to send after a input change is made to the gui page as it loops and watches for a change made to then process the change made and change the tablet and send it out to the board. That part works.