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2014 Gen1 blend door / air flow issue (fuse 5 pull was not effective)

1990 Views 19 Replies 5 Participants Last post by  Lug_Nut
My 2014 has developed a cabin air flow direction issue that manifests as if no air outlets are open. This is not an air temperature issue. I get no air flow regardless of temperature setting.
I've tried the "pull fuse 5" stepper motor reset. That appears to trigger the motor to re-teach itself its zero point, but I still obtain no air flow through any of the outlets. No air out the defrost ducts at the base of the windshield. No air out the dash vents. No air out at the floor.
The blower fan motor speeds up and slows down with changes to the manual fan speed control. When the fan is running slowly / quietly I can hear a sound akin to a motor pulsation that occurs when changing the center stack icons from dash to floor to defrost. There is no air delivery change accompanying the icon selection.

Re-circulation, whether off, or active, or automatic, makes no change in the air flow. The air inlet under the hood in the cowl at the base of the windshield is not blocked with leaves, snow or ice.

Is there a linkage or rod or other mechanical connection between the stepper motor and the moving air flap(s) that might have become disconnected,
Or do my symptoms imply a vi$it to the Chevy dealer is in my near future?

Oh, and Merry Christmas to you and yours.
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Motor turning but blade is not? Fan blade not connected?
 

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Discussion Starter · #3 ·
I hear sounds as if the fan is whipping air around, making turbulence, in an enclosed, no outlet, chamber.
Were the fan loose on the motor shaft I'd expect I'd either hear an additional sound from the slipping of the fan on the shaft, or, had the fan come completely off the motor shaft, just a faster / higher frequency motor hum at increasing settings for motor speed .
 

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Discussion Starter · #4 ·
Here's an update / clarification: There IS air delivery to the floor outlets.
There is no change when any other outlet choice is selected. I do hear something activate and make a sound like it is moving (stepper motor?) when other outlet choices are selected, but there is no change in the air delivery. Selecting the floor+windshield keeps the air delivery on the floor only, same with selecting the dash vents, same with defrost. There is a sound from within the center stack with each selection, but no air flow outlet change at all.

I'm really leaning towards a mechanical disconnect. If I'm lucky, I can pop whatever back into position, but with my typical non-luck, I'm suspecting I'll find something broken....

Thanks for allowing me to vent. (pun.... sorry.)
 

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You may be able to access the vent door actuator by removing the glove box. Perhaps clogged cabin filter may be restricting are flow. Try removing the air filter to detect a difference in air flow. Just blowin some hot air (not)...
 

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From your initial description, I thought that a mechanical linkage had disconnected/broken. Does someone have a parts diagram to post here?
 

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Here is a service manual description on how to calibrate the actuator motor without a scan tool:
Alternate Method (without Scan Tool)
Note: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.
1. Clear all DTCs.
2. Place the ignition switch to the OFF position.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Remove the HVAC control module fuse for a minimum of 10 seconds.
6. Install the HVAC control module fuse.
7. Vehicle in Service Mode.
8. Wait 40 seconds for the HVAC control module to self-calibrate.
9. Verify that no DTCs have set as current DTCs.
Looks like the temperature and mode actuators are on the left side of the HVAC box and are accessed by removing the brake pedal assembly. I've this type of work, you need a flexible back. The alternative is to remove the HVAC box...a very big job that involves disconnecting heater core coolant lines and A/C lines.
 

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Discussion Starter · #8 ·
Thank You, T.Y. (not an echo...)
I have already performed steps 1, 2, 5, 6, 8 and 9. Steps 3 and 4 were not as there was no removal and reconnection.
How is the vehicle placed ".. in Service Mode" for step 7?

Flexible back? not really, not since my discectomy and laminotomy.
But I did just spend part of last week on my back to install the under-dash defrost vents in my 1969 Sonett, so I'm all warmed up, I've topped-off my ibuprofen supply, and I'm on vacation for nearly a week to recover if needed.
Hey, if my 7 year old car has no heat, I can still I can count on my 53 year old car to clear the windshield.
 

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for step 7, press and hold the power button for 5 or 10 seconds without stepping on the brake
 

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The posted steps, except 3 and 4, have been performed. No change in the situation.
Now to commence the disassembly to gain viewing access.
Please post pictures if possible.
 

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Discussion Starter · #12 ·
What did I say? Oh, yeah, I remember:
If I'm lucky, I can pop whatever back into position, but with my typical non-luck, I'm suspecting I'll find something broken....
Well there's your problem...

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The floor vent air flow I feel is just air 'leaking' out the side of the heater box where the stepper motor used to be attached.
The sound of the stepper motor moving is due to the motor moving.
The lack of air direction change is due to the motor actuator not being connected to anything.

This view is with the lower dash, knee air bag, and floor vent ducting removed and looking up from the floor.
The brake pedal arm is the black item along the lower left of the image, accelerator pedal arm at the lower center.

The replacement is more than I want to do, so off to the dealership for service it goes.
 

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Thanks for the picture! At least you know exactly what the problem is.

Seems odd that it would just break off like that. Could it have been damaged during a previous dealer visit to address a different issue?
 

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Discussion Starter · #14 ·
Unlikely during my ownership, but then I'm not the first owner.
I've owned the car for 3 1/2 years. I've had it in the shop three times: coolant circulation pump, battery temperature sensor software update, right front wheel bearing.
Other than those three, there was one day this summer when she used it when hers was in the shop. Otherwise I've been the only driver.
I've not ever seen any pieces of plastic on the floor. I can't find any that might have fallen onto a 'shelf' and not hit the floor. I can only surmise that someone cleaned-up to hide the problem.

But then why did my air direction control problem not appear until last Friday?
 

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But then why did my air direction control problem not appear until last Friday?
I think it was damaged (cracked) at some point in the past and the cracks kept growing over time with road bumps, motor use until it was hanging by the proverbial thread and finally broke free.

I suppose it could have been installed broken in the factory, but I think prior service at a Chevy dealer more likely.
 

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Discussion Starter · #16 ·
I had arranged last Thursday the 30th to have my car go in to be 'evaluated' this past Thursday the 6th, their first opening, but due to the service writer not setting the date for the first Thursday in January, and instead setting it for the first Thursday in FEBRUARY, that drop-off didn't happen this week. I've had them reschedule me from the 3rd of Feb. to next week, the 13th of Jan.
I spent the day instead pulling out the one remaining "mode" control gear and last bits of the shattered housing that used to secure two gears. I set and secured the air flow flap levers in position to get defrost by using a rubber band on the flap levers.

The dealer doesn't have the parts I need in stock, and will not order them until they review the situation themselves, so I expect I'll be on the hook for expedited shipping in addition to what looks like it will be a significant labor charge to disassemble and then reassemble.
 

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Discussion Starter · #17 ·
So I dropped the Volt off at the dealer on the evening of Wed. the 12th. By noon the 13th they call me and said the control system was broken and that it would need some parts ordered. I informed the caller that I already knew that, and that I had previously told them which parts were needed, and that the dealer's parts department had already confirmed to me that the parts were in stock at the supplier. The caller asked for approval to special order the parts. I approved and offered to pay expedited, overnight, shipping to get them in with less delay. I picked up the car later that afternoon of the 13th and asked the expected delivery of the parts I needed. The in-person reply was that since it was late on Thu., the warehouse wouldn't get the order processed until Fri., Mon. was a holiday, so there wasn't much to gain by expediting. They persuaded me the usual 4~5 business days for standard shipment would not be much longer than an 'overnight' rush. The dealer would notify me when the parts arrived to schedule my car back in for tear down and replacement.
Fri. the 21st I've heard nothing. I call. "The parts are back-ordered. We don't know when they'll be available." What happened to the two times (Jan. 3rd, Jan 13th) I was informed the parts were in-stock ready for shipment? I went on-line, ordered new G.M. parts that were in-stock from a G.M distributor paid for them, and called the dealer back to have them cancel their parts order and pending service. "You owe us $169 for the special order." I pointed out that the so-far verbal agreement for the parts was based on their confirmation of availability with their supplier and the dealer's assurance they would have the parts within 5 business days. Their failure to procure those parts in their stated time frame led to them failing to uphold their side of the verbal agreement to provide parts.
 

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Discussion Starter · #18 ·
The "in stock" parts I ordered weren't shipped out from the supplier for a week! No high rated e-bay review for you. The parts arrived here about 2 weeks ago, but I held off until better weather for driveway work, and that was this 'weekend'. Here is the gear set I received and what I had removed:

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So here's the preparation / access state needed:

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At this point the service manual claims the brake pedal support has to come out, requiring disconnecting the ABS module and the master from under the hood, unbolting, pulling back and lifting the interior cross member. Once the dash pad was off I thought there might be 'just' enough space to drop the gear set in from above so that's what I did. Access to the gear set securing fasteners was insanely tight with the brake pedal support still in place, taking more than an hour to install the screws, but required no under-hood work what-so-ever.
It's mostly re-assembled now. The air flow direction control works like it never could have before.
 

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Holy mackerel Lug_nut! What a daring repair! This DIY saved you thousand(s)...Did you have to pull the propulsion battery disconnect? Did everything snap back together? How would you rate the difficulty of this repair? What do you suppose caused this gear mechanism to chew itself up? Definitely deserving of a reward for this one...
 

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Discussion Starter · #20 ·
Better than saving tens of hundreds of dollars is being able to KNOW that everything is reassembled correctly. No missing fasteners, no loose screws, no pinched wiring, no tab A not inserted into slot B. The car is noticeably quieter now.
I pulled the air bag fuses, but I had questions about battery disconnect. One step says pull the negative from the 12 volt, later it says to turn the steering wheel left to uncover a fastener. I thought the wheel would be locked with no battery power.
Level of difficulty? It's like eating an elephant: one bite at a time. Without a repair manual I'd have not attempted it. Had I needed to pull the steering column and brake pedal support it would have been much worse (my opinion). That's why I spent the inordinate amount of time struggling to get the gear housing screws in without those items out of the way.
Based on the date codes on every item so identified (all late 2013 or Jan 2014) there are no replacement items. I don't think that was a reason for anyone to have been so deep into the geographic center of the car other than during its assembly. The gear set is well protected in the narrow confines. It can't be kicked, it can't be pried to either side enough to crack. My mind is made up that the gear set was broken when the cross brace was swung into the car and that the broken bits were picked up and binned before it moved to the next assembly station.
 
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