HVAC problem with UAS upgrade in '18 truck

[Gibbs]

Today I installed 68366553AA HVAC module for a 2018 2500. It almost instantly corrected the temperature problem. The indicator lines up perfectly with the servo position and the arrow tracks up and down smoothly with no skipping like before.

The problem now is the Rear Defrost icon is grayed out. I don't have rear defrost, but I do have heated mirrors. I'm assuming the mirrors won't work if the icon is inoperative. Is this correct?

The icon worked before with the old module with UAS radio and with RA4 radio.

Any ideas on this? This is one feature I use all the time, and it seems like I traded one problem for another... Dang it, so close!

Edit to add: if I press the physical button on the dash for Rear Defrost, the LED flashes 3 times then goes off.

 

[Mpgrimm2]

The radio may just need to relearn/get the config from the truck's BCM and may take a bit to do it (hour or two?)... Or as DeereGuy mentioned, disconnect the battery 5-10 mins to force it to reset/relearn and reconnect. May take awhile, but it will be reconfigured once the SXM radio button and backup camera show up.

http://www.ramforum.com/index.php?posts/1458159]M² Mods.

 

[Gibbs]

Thanks for suggestions. I disconnected batteries for approx 30 min, then reconnected and waited until radio reset (Several random key cycles in the midst of doing other stuff, until SXM logo reappeared)

I still don't have Rear/Mirror Defrost functionality. I'll revisit it tomorrow and see if anything's changed. Perhaps its something screwy with this particular module...
Heck, this truck is screwy, lol.

 

[Gibbs]

Update

So I went out early this morning to check my truck and still had no defrost. I thought, Oh Well, so I rinsed the pollen off and went back in to get ready. Came back out an hour later to leave and figured I'd drive my truck to work today. Started it up, selected climate to fire up the windshield defrost, and lo and behold, the rear defrost was there. And it works...
Hallelujah, I'm so excited!

This time delay crap really throws me off.

Thanks Mike G! And Mike D!

 

[Mpgrimm2]

Us too. It really makes troubleshooting harder.

Thanks for the posting update.


http://www.ramforum.com/index.php?posts/1458159]M² Mods.

 

[Gibbs]

You're welcome. Thank you for the continuous support.

 

[Guido2112]

Thanks for the info!

I just ordered the 68366553AA HVAC module for my truck now.

 

[Gibbs]

Thanks for the info!

I just ordered the 68366553AA HVAC module for my truck now.

What are the specs on your truck out of curiosity? 1500 or 2500? Tradesman, SLT? ...etc

I assume you have the 68105017xx module in it now?

 

[Guido2112]

What are the specs on your truck out of curiosity? 1500 or 2500? Tradesman, SLT? ...etc

I assume you have the 68105017xx module in it now?

I have a 2017 1500 Express....no clue on what module I have, but have the same exact issued you had.

 

[Gibbs]

I gotcha, I really hope that takes care of your issue. Keep us updated

 

[Mpgrimm2]

I have a 2017 1500 Express....no clue on what module I have, but have the same exact issued you had.

I assume you have the UAQ or UAS radio in your 17 truck? (Likely with the xxxx8186 or xxxx3973 module for 7 speed trucks). I will repost this again:

As DeereGuy stated, it appears that...
- 68366552AA = 1500 trucks w/8.4 radios (MTC & ATC)
ie factory 7 speed fan (w/Variable Displacement A/C Compressor)

- 68366553AA = 2500/3500 trucks w/8.4 radios (ATC)
ie factory 4 speed fan (w/Sgl speed A/C Compressor)

Cost for each is in the $120-$130 range.

We can't confirm 100% yet until someone installs oneb to test, but you likely need the xxxx6552 module for your 1500 (vs 6553 for the 2500/3500).

http://www.ramforum.com/index.php?posts/1458159]M² Mods.

 

[DeereGuy]

I agree likely he won’t have a 7th Speed with the 68366553AA module. The 68366552AA is for the 1500s due the difference in A/C compressors.

 

[ckleinfeld]

Subscribing.

Having the same blend motor issues with my UAQ (infotainment kit). Didn't notice it so much on heat, but very noticeable when switching to cold. I also see quite a lag with the on-screen displayed slider when using the buttons.

2015 Express CC, UAQ PN 68331631AH, 7sp MTC, 68268186AA-001 HVAC Module

 

[Mpgrimm2]

Subscribing.

Having the same blend motor issues with my UAQ (infotainment kit). Didn't notice it so much on heat, but very noticeable when switching to cold. I also see quite a lag with the on-screen displayed slider when using the buttons.

2015 Express CC, UAQ PN 68331631AH, 7sp MTC, 68268186AA-001 HVAC Module

You will likely need to swap out the 7spd 13-17 HVAC module for the 18 one...

68366552AA

M² Mods.

 

[ckleinfeld]

You will need to swap out the 7spd 13-17 HVAC module for the 18 one...

68366552AA

M² Mods.

Ordered, thank you!

Sent from my SM-G930V using Tapatalk

 

[ckleinfeld]

Curious if there are different SW versions, or revisions for the '552AA module. I tried the attached ( bought used on ebay) and saw the same response as the original module.

Sent from my SM-G930V using Tapatalk

 

[Mpgrimm2]

Curious if there are different SW versions, or revisions for the '552AA module. I tried the attached ( bought used on ebay) and saw the same response as the original module.

Sent from my SM-G930V using Tapatalk

Have you tried disconnecting the battery for a minute or so to force the radio and modules to reset? (It will take a good while for the radio to reset fully, ie backup cam and SXM will be missing until it's finished reading the BCM config.)

M² Mods.

 

[ckleinfeld]

I did not, thank you for the pointer. I'll give it a shot this evening.

Have you tried disconnecting the battery for a minute or so to force the radio and modules to reset? (It will take a good while for the radio to reset fully, ie backup cam and SXM will be missing until it's finished reading the BCM config.)

M² Mods.

Sent from my SM-G930V using Tapatalk

 

[Mpgrimm2]

I did not, thank you for the pointer. I'll give it a shot this evening.

Sent from my SM-G930V using Tapatalk

Let us know how it goes.

Side note: Back when the Single Zone ATC mod was first figured out on the 13-17 trucks several people noticed differences with the settings/features when getting used HVAC modules (from higher trim trucks) vs new ones without any saved BCM config in them.

M² Mods.

 

[ckleinfeld]

Let us know how it goes.

Side note: Back when the Single Zone ATC mod was first figured out on the 13-17 trucks several people noticed differences with the settings/features when getting used HVAC modules (from higher trim trucks) vs new ones without any saved BCM config in them.

M² Mods.

No luck. Left the battery disconnected for ~45 min. Radio reset, lost Sirius and booted with dual zone climate control. Key cycled; XM and single zone climate control returned, assuming it read the BCM fine. On-screen temperature slider was still not calibrated to the mixing door position. Full hot is close, within 5°, but full cold falls short by ~20°.

Not the biggest deal, certainly something I can work around. Just annoying

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