After swapping radio, no HVAC controls - Pontiac G8 Forum: G8 Forums -
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post #1 of 4 (permalink) Old 10-12-2018, 11:41 PM Thread Starter
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Location: Niles, IL
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After swapping radio, no HVAC controls

Hello, I am a newbie here and this is my first post. I have a very base model G8 with no options. After reading the DIY VIM article, I decided to swap the single CD radio w/ manual HVAC controls, with the 6 CD radio and digital HVAC controls. I did all of the VIN # EEPROM programming as described in the article and even matched the "pairing key" values of the new faceplate and radio unit with that of the original radio/faceplate unit.

The 6 CD radio works properly. There are no "security lockouts" messages. But the HVAC controls, do not seem to respond properly. The fan speed does not respond to the +/- controls. It does change when pressing the "Recirculation" button. The Ext. Air temp displays "-40" (ironically it is about 40 deg. outside here), which may suggest that I am missing other sensors and equipment. Aside for displaying some indicators on the screen, all of the other buttons seem to be ignored.

Does the BCM need to be programmed for a different HVAC control? Has anybody played with this or have any knowledge of this condition? Or is this my first experience with a digital HVAC system? Thanks in advance for any responses or suggestions.
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post #2 of 4 (permalink) Old 10-13-2018, 08:29 AM
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The base model HVAC is single zone whereas the radio you swapped in is dual zone. You are probably missing a few interior temp sensors and circulation doors that it's expecting to see.

2009.5 G8 GXP SRM 6MT
-Kooks 1-7/8 LT, 3" Solo, RotoFab CAI, Full Zeta II suspension with BCs, Monster LT1-S & Tick Master Cylinder, 3.91 w/ TrueTrac
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post #3 of 4 (permalink) Old 10-13-2018, 01:45 PM
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I have to agree with "yutzybrian" >>>>>>>> If you *can't see* a small grill in the trim panel (about 3" to the left of the display panel), then you are missing the interior temp sensor circuit (which is needed for proper auto temp control). An I suspect it causes the loss of auto fan control and (as in your post, it appears to cause the loss of manual fan control as well). The light sensor (located at the forward center of the Instrument panel) is probably also the wrong type for dual control function. The correct one also includes a left an right side sun/heat detectors. It allows the HVAC to modify the left vs right side actual out temp when in the dual mode, to compensate for excess heat that might be sensed by one side or the other (based on where the sun is hitting on the car). Also the Base HVAC gets one temp control actuator, whereas the Automatic dual zone HVAC version, gets a dedicated left an right side temp control actuator. This might mean your trapped between a rock an a hard place in trying to get it to work as a dual zone mode system.
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post #4 of 4 (permalink) Old 10-14-2018, 01:16 AM Thread Starter
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Location: Niles, IL
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Thanks for the responses. I didn't expect so many hardware differences when I first approached this.
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