RESOLVED - AUCAR HEAD UNIT - issue with AC compressor clutch aways engaged

Hello everyone, I want to start a blog post here informing and getting anyone together that has a AUCAR Android 11 Head unit to discuss and petition to AUCAR to fix the following issue.

There is a AC "hard button" on the bezel as well as a "soft button" on the touchscreen environmental control page that is non functional. I have seen in youtube videos where people who have this unit also mention that the buttons dont seems to control the on off status nor show status of the compressor. but i dont think they know the extent of the issue. the units current hardware/and software drop version is engaging compressor to be hard on based on just the blower fan being engaged into any speed other than OFF. and stay engaged at all times all modes all temperatures and the AC ICON is never showing status for compressor being on nor would it flash if faulted like it should and does on the factory panel.

the issue is this, anytime the environmental system is on (by pressing any mode button OR by adjusting the temp OR by pressing the on/off button on the software page, it powers up control to the environmental system. also note that the only way to turn off the system is by only the software page on/off soft button

now... Regardless of mode or temperature setting, even when full hot vent or on full hot defrost or floor only or just wanting vent with a cooler temp but no AC or just vent but with heat, the AC compressor clutch is always engaged. blower on = clutch is engaged.... period. this is wrong.

This is unacceptable to me that fuel economy is being affected and that i cannot even run full heat without the AC compressor engaged.

I have contacted AUCAR and am awaiting response and i Ask others with the unit to go test this and see for themselves that this is a deeper issue as ive described. I think some may believe that the compressor is modulated on or off depending on temperature set which is NOT the case.

For now, as a temporary workaround, i had to take the AC on line coming out of the factory plug pin 13, depin it and placed an external switch on it to open the circuit so i can use it as a "Power to pass" switch or to be able to run heat or just blower without the AC compressor being on. this switch is temporary until i can get AUCAR to review and fix this issue. Obviously, having to come up with and install this external switch was so unacceptable to me especially when there is both a Hard and Soft Button on this unit that should be performing that function and because they do not work or have any function to those buttons. i am hoping other owners with the same software drop can check and report in if theirs are behaving the same and join me in contacting AUCAR to fix this so i can remove my temporary external switch and repin the wire back to the factory diagram layout for that connector and have the unit resume control of the signal on that wire.

 

My hard buttons work the same exact way as the "soft' ones. Everything works as it should

 

FYI.....this is a totally unacceptable workaround that i have come up with and had to go temporarily perform because the Head units bezel and soft buttons are not performing the simple function of the factory control panel button they replaced. I circled the factory switch panel "A/C" switch this head unit should be performing equal function to and then circled the temporarily switch i installed now as a work around until they respond and i (and hopefully others) demand a software fix to their unit. I am annoyed i have to come up with an interim workaround like this and that they have not revealed this flaw and i had to stumble across it . This can be tested by tapping that wire with a meter and seeing its always commanding on or even by simply placing the unit into full hot with defrost or floor or vent only and then opening your hood and feeling the output hardline from the compressor become ice cold when you turn on only the system blower fan to any speed and even when the temp settings are already on full hot. when, the factory panel is slave in, i can goto full hot and vent mode and the compressor is not engaged nor is the ac lamp illuminated until i decide to push it and engage the ac compressor.

 

Are you able to test like i mentioned on Post #3 or have you already and when you say yours functions normal, what firmware do you have because ive also heard earlier firmware didnt have this problem (rumored)

also, does the AC icon on the software screen turn blue or always stay grayed out regardless of trying to press it or the bezel AC switch? mine always stays grayed out

And i have mostly NOV 2022 firmware versions for all software components listed on the config page.

 

I am not going to pull it to test it when it works correctly. The AC turns white when it comes on, it doesn't matter which button I press. Did you read through the giant thread about these? I have upgraded Sergey software, but I didn't have climate control problems before

 

Im sure im missing the full scope of this op’s post but I thought our ac compressors run during defrost from the factory to act as a dehumidifier?

Is this HU software suppose to change the oem operation of the system?

 

Should just return it. These units aren’t worth the hassle or Russian firmware to get them where they should’ve been to begin with

 

Boy isn’t this the truth. All that Russian firmware really does is make it look more modern but its a great way to flush $100 down the toilet, I did that already, lesson learned.

 

To be honest, this newer unit, the 8Core 8G/128G android 11 is amazing for everything else i just didnt notice this issue unit now when i was wondering why my MPG was acting like AC on. I have full 4G LTE with Dual band antennas running MIMO and placed 90 off from each other and the greater than the minimum 3.1 feet apart, SIgnal strength is way better than my cell phone. also using the factory GPS antenna in the shark fin, adapter is a SUMI to SMA. also i retained the SiriumXM coax and pullet it back and plugged it into a dedicated XM commander receiver (another special Sumi-SMA adapter did that trick) to get true sat-radio signal and not streamed over cell so i can use it anywhere and its coming in on the AUX Audio input. several cameras installed in addition to the factory backup tailgate. plus i can toggle to my truck bed camera when backing up when tailgate is down and hauling dirt bikes or if i just want to look into the bed and over the bed sides and backwards from the 3rd brake light vantage point. plus many more things the Speed is exceptional. no lag, pages are laid out great. torque pro launches on bootup, gives me everything i want, including trans fluid temp at pan and TC. what more could i want? russian software not needed for this newer version.

But as i said if you re read, its engaged regardless even when full HOT and just on floor or vent or mix of floor and vent. Defrost maybe you are right, but ive always engaged ac if i wanted to lower the humidity while defrost, factory panel gave that option. not going argue that its on or off when defrost mode by factory design...but i do think you are wrong because if you have the full diagram, youll see that the AC button nor the defrost drive the AC lamp, instead it is driven on or off by the AC. amplifier i would expect that if the defrost mode commanded to the amp were also engaging AC, then the AC lamp would illuminate. check and see, you can toglle AC on or off yourself while in defrost, its not automated as you are suggesting. I also slaved in the factory panel today and checked the compressor is not engaged on defrost unless i also toggle AC. My truck is a late model 2015 last of the 2nd gens with some provisions in it that weren't activated until 2016, but fortunately my truck have some of the pre planned wire changes for several 3rd gen systems installed and capped. they have come in handy already for other mods where it saved me from running wires and was able to use some of these provisions within the hybrid harnesses in my truck that came factory installed

The point is it shouldn't engage the compressor regardless of mode and all the time like its doing

 

I don’t know about yours but on my 13 the compressor kicks on and off all the time regardless what setting its on unless I shut the fan off then it stop’s completely. Its worked this way from the day I bought it and no different with this head unit for me.

 

was editing my post while you pasted an unedited version....

as i added above, my truck is a late late serial number 2015 and maybe they changed some component mod version in the ac panel or ac amp, i dont see any delta in the Wiring diagram for a 13 vs 15, but its possible that my truck had some newer component. but as i said above in the edit, the AC lamp om my truck is driven by feedback from the ac amp when the compressor is engaged. but i believe you guys that yours may work the way you described, maybe AUCAR copied your trucks and mine is different component mod level. believe me Im the chief engineering and certification test pilot for a major business jet manufacturer and surely my factory panel does not engage AC all the time either. yours may, mine doesnt. I could at any time, turn off ac and leave blower on when approaching a steep grade climb up a mountain when its high and hot. and i could toggle AC on or off during defrost. i slaved it back in and rechecked it again and im telling you fact I guess what you guys are saying is that on your trucks, merely turning the blower fan from off to any speed position engages your clutch on your compressor? wow, and your AC button does what exactly if your compressor is always on when the fan is other than off?

 

https://www.tacomaworld.com/threads/a-c-on-with-defrost.7160/

 

Are you guys not reading my posts properly, again, 2nd time, i said anytime the fan is on or heat is on regardless of mode the compressor should not be engaged

you guys keep sidetracking this with your redirect to a post that says QUOTE.. "disable the A/C from coming on when selected the mixed(floor/windshield) and windshield only modes"

please dont sidetrack this The compressor should not be on when normal vent and full hot

 

Yes I can read. No clue why your truck is engaging the compressor for every possible environmental selection. What we were pointing out is toyota intended to fire the compressor regardless of temp setting meaning both cool and hot when defrost and defrost/floor are selected meaning your HU may not be the issue as you are implying. Only suggestion I can offer is uninstall your HU, reinstall the factory hvac controls and see if the system goes back to normal.

 

Pleas everyone.... this thread's focus is on calling out to any members who have an AUCAR unit if their AC ICON stays grayed out regardless if pressing the soft button or the bezel hard button. it is a feedback request from AUCAR unit owner and if theirs are different than mine, plese indicate what firmware dates you have installed and reported on you config page

 

I appreciate the kind reply, have done so, i have no argument and believe that others may have AC on when in defrost or defrost and floor mixed, maybe i havent said that clearly, my apologizes, so ill clarify that when i said regardless of mode, it didnt mean that it should always be off in any heat mode, what was meant in the original post and what was said was that its shouldnt always be on regardless of heat mode (the ones that it shouldnt be on)

way cool, thanks and yeah, ive reinstalled and my old panel doesnt engage ac in any mode unless i command it on by the ac switch, and for my panel thats even when in defrost but i am not insisting yours should behave the same as mine for defrost.

i will say, that the ac shouldnt always be on anytime the blower is other than off

need some AUCAR owners to inform if theirs are the same, one guy mentioned a partial reply, but he didnt indicate if his ICON is grayed out always hoping he chimes back in and other owners too, i think AUCAR screwed up the function on their latest firmware and software drop that came in my unit the NOV 2022 and i dont have access to the older drops that other may have, hence my call for owners to reply

thanks

 

After communication with AUCAR field engineer and relaying the testing i performed, they concur that the unit is outputting a ground on the pin 13 anytime the blower fan is on and this isnt suppose to be the case. On the factory control panel, pin 1 ground is only connected to Pin 13 output to command compressor on only when the ac button is pressed over and above the blower fan being on. the compressor should not be hard commanded to on anytime the fan is turned on to any speed any mode and temp. and certainly the AC lamp should be matched to indicate the compressor is commanded on or off and to flash during fault condition. this is per toyota engineering response to me as well. so AUCAR today, agreed that this needs to be fixed, so the ac button or icon being pressed is asserting or removing ground onto the command line voltage coming from the AC amplifier via pin 13 to engage the compressor and then provide a ground status back to the panel pin 10 to drive the lamp. they are reviewing the software to determine how to correct the issue so that the icon can be toggled on and off (blue and gray) independently and anytime the blower motor speed is commanded to any speed other than off ... Currently, on the unit i have and software version i have (NOV 2022 software drop), output 13 is always grounded when the blower is turned on and regardless of mode. additionally i had discussion that the ICON should appear blue Not only by mere AC control panel push button state but it should instead be driven on/off/flashing status as asserted by the ac amplifier back to the control panel via pin 10.

the rationale for this follows the toyota operating manual and toyota engineering confirming via email that in short says the factory lamp has dual purpose and will flash when there is one of 13 possible faults that prohibit the ac from being commanded on i.e. compressor speed vs engine speed, high pressure, low pressure etc etc, a list of 13 possible sensors or component failure that can inhibit the clutch engagement command.

this is being looked into by AUCAR software engineering and reworked via next software drop per my request and so it maintains the prescribed lamp indication for fault indication flashing as well as compressor on or off status.

seriously, other than this single issue which will be resolved, this unit is amazing, especially with the capability of extended PIDS and gauge display via not just canbus, but via k line modules too like the ABS and TPMS modules. and the optional additional connection that can be dreamed up and interfaced like the things i have done are awesome. its ashamed that this one hiccup has occurred, but their support is remarkable and quick and receptive. i am truely happy with this latest version with the 8 core processor and 8G/128G 6 weeks now and not a single other problem with it nor are there any nuisances with this unit.

i am confident with how responsive they have been that this single issue will be resolved permanently and in short time.

 

yeah sounds like you have the 6core android 9, unit and sergey software, this is the newer 8core, android 11 unit where there is no sergey stuff for it and this is with the latest software drop only that this is occurring... so i dont think your unit is capable for comparison testing because it cant take this NOV 2022 software drop.

plus i wasnt asking anyone to pull their unit and measure, i was just asking for anyone with this latest software drop (NOV2022) to report back if their ac icon would change state between grayed out and blue anytime they toggle it when the blower is already on and in vent mode. i think they screwed up the code for this item on this latest software release.

thanks anyway

 

Glad your on the way to a fix for your problem, it’s great when that happens.

 

You're right, my apologies. My bad