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View Full Version : vent door stays closed on my LBZ, looses its memory until reset


ron54
05-28-2007, 18:44
my vent door stays closed even when rcirc is off. If I remove the HVAC fuse it resets and works (opens & closes normally) for about a day. My dealer doesn't understand how it looses its programming without giving any codes. They want to replace the acuator now, but I'm weary if thats realy the issue.
Duramaster
05-28-2007, 20:48
Has the dealer checked to see if the software is current in the HVAC controller? Have they checked for bulletins? I found no bulletins for your concern. THe dealer also has the ability to perform an actuator recalibration procedure. Good luck, :)
ron54
05-29-2007, 02:27
Has the dealer checked to see if the software is current in the HVAC controller? Have they checked for bulletins? I found no bulletins for your concern. THe dealer also has the ability to perform an actuator recalibration procedure. Good luck, :)

They performed the recalibration procedure and it worked for a day. It appears to be loosing its memory upon starting the motor, but only after several motor starts. Nothing else in the vehicle is loosing its memory, and there are no codes.
More Power
05-29-2007, 17:26
How has the engine been starting? Does the starter spin fast and the engine start quickly? If not, you may have a battery/cable issue that is allowing the voltage to drop to a level that confuses the memory of some of the various systems.

Might be helpful to measure the battery voltage at the HVAC fuse while cranking during a cold start.

Jim
ron54
05-30-2007, 07:26
How has the engine been starting? Does the starter spin fast and the engine start quickly? If not, you may have a battery/cable issue that is allowing the voltage to drop to a level that confuses the memory of some of the various systems.

Might be helpful to measure the battery voltage at the HVAC fuse while cranking during a cold start.

Jim

battery cables are tight, and the vent works opens & closes at 50 degrees and below. Above 50 it only works if I reset the fuse for about a day.
Dakster
06-03-2007, 09:50
When you figure out what caused it let me know so I can make mine forget to yutn off everytime I restart. I keep forgetting to turn my recirc on (defaults to off) and I always end up smelling the nasty gas car/truck in front of me in traffic.:D
ron54
06-03-2007, 17:59
When you figure out what caused it let me know so I can make mine forget to yutn off everytime I restart. I keep forgetting to turn my recirc on (defaults to off) and I always end up smelling the nasty gas car/truck in front of me in traffic.:D

The dealer replaced the actuator, and it worked for a few hours, and again closed. Something in the programming is causing it to close above 60, and work open or closed below 60 degrees. Dealer has a call into TAC. Personally, I think its a programming issue, but they can't reprogram without GM approval. All they could do is recalibrate, which didn't work.