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Chris_W
Chris_W 9/5/2012
2005 Chevrolet Tahoe LS 8Cyl4.8L - Body & Interior
No air flow out of front vents, reagrdless of fan speed setting.
Tahoe with front and rear AC. AC works fine using either the front (dedicated to rear air control) or rear controls, however there is no air flow from the front vents regardless of setting 1-5. I have removed the blower motor and resistor, but do not know which is most likely bad.
Any thoughts are appreciated.
Thanks!
5 Answers
  • HouseCallAuto
    HouseCallAuto 9/5/2012
    First of all I am interpreting your details as that the blower motor is "NOT TURNING ON". If you are saying that there is air blowing, but the air is simply not blowing out of the front vents you will update the post and clarify. Run direct power to the two terminals of the blower motor to test it. 12 volts and a ground. If it does not run then replkace the blower motor and the blower resistor together.
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    HouseCallAuto
    Chris_W 9/6/2012
    Thanks for your reply. There is no air flow through the front vents what-so-ever. Air flow through the rear vents works as it always has. I assume the front and rear vents operate on a different blower motor as they are operated with a different set of controls. Front vents operate with controls on the dash. Rear vents operate from controls in the celiing either upfront by the driver or behind the driver in the first row of backseat. That said, I am not a mechanic. Hope this helps.
    HouseCallAuto
    Chris_W 7/25/2013
    HCA-Reaching out for advice this time. You have been a great teacher to me in the past. 05 Chevy Tahoe LS 4.8L 99k miles. Original owner. Mechanic reports the hydro boost on brake system is going bad. Pads/rotors never replaced/turned, but still in good shape. Can feel slight shimmy in pedal. $800 to replace. Any experience with this? Also reported water pump w/signs of leak, but not leaking when inspected. $200 to replace. All worth the repair cost, given age/mileage of rig? Thanks, as always.
    HouseCallAuto
    HouseCallAuto 7/25/2013
    The shimmy is caused by warped front nbrake rotors. Unless the hydraboost is leaking fluid badly leave it alone. I can only remember replacing one in all my years so my gut says there is nothing wrong with it. It certainly will not cause a shimmy. Water pump leakage is common and if leaking replace the pump. $200 is a good price to replace the pump but that sounds too cheap for parts and labor. Leave the hydraboost alone. Some leakage after a few years is normal.
  • HouseCallAuto
    HouseCallAuto 9/6/2012
    Then it is as I said. Under the dash from the passenger side, remove the plastic sound insulator cover to expose the HVAC housing and blower motor (the round looking part of the case pointing down). Unplug the connector from the blower motor and you can check and see if there is battery voltage on one wire (the purple wire) and the black wire always remains a ground. Check for battery voltage with the key on and the blower turned on. If you have 12 volts on the purple wire and a ground on the black wire and the blower does not run, then the blower motor is junk. Check that and update me and I will continue with the next step later tonight. If there is no voltage on the purple wire make sure the fuses are good. the fuses you need to check are labeled HTR / AC (30 amp) located in the instrument panel use box. Also check the 40 amp maxi fuse labeled BLOWER in the underhood fuse panel.
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    HouseCallAuto
    Chris_W 9/6/2012
    Thanks! I pulled the cover off, disconnected the plug and pulled out the blower last night. Am ready to follow the next steps when I get home after work tonight. What do I need to check the battery voltage on the purple wire? I drive right past an aut parts store on the way home and was planing to buy a new blower motor and resistor module, just in case it is either one or both. I can also pick-up the "tester" while there.
  • HouseCallAuto
    HouseCallAuto 9/6/2012
    You can buy a simple 12 volt automotive test light for like $10. Clip the lead on a good ground (like a door hinge bolt or similar) and use the pointed end to touch your voltage source (the purple wire pin in the blower motor connector). If the test light does not illuminate at first, make sure that your ground connection is good by jiggling it while touching the purple wire just to be 100% sure that you really have -0- volts reading if that is the case.
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    HouseCallAuto
    Chris_W 9/6/2012
    Update-picked up tester, blower motor and resistor. Checked both fuses, they are fine. Had no luck with the tester, tried different spots for the ground, still no light. So-began thinking must be the resistor. However, when I removed wire assembly that comes from under the dash to the resistor, I noticed the plastic around the black wire was melted. I quit at this point. I read somewhere there may be a service bulletin that covers this issue. I will check with Chevy tomorrow. Thanks for help!!!
  • HouseCallAuto
    HouseCallAuto 9/6/2012
    15862656 is the part # for the melted connector and wires (comes as a splice pack)
    89019089 is the part # for the resistor if the truck has a console
    89019088 is the part # for the resistor for without console
    The bulletin is a TSB which is not a recall. I have repaired this at least 3 times on various GM trucks. Don't let the burnup scare you. Get the connector and the resistor but I strongly recc you also replace the blower motor as well because the amperage draw from the old motor may be a contributing factor in the meltdown and again I would use ACDELCO only as there have been documented instances where the aftermarket brands on this application draw too many amps even when new and cause the same meltdown to repeat.
    I recc you use genuine ACDELCO parts which these part #'s are for.
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    HouseCallAuto
    Chris_W 9/20/2012
    Many, many thanks for your advice-replaced all 3 parts and all is working. I greatly appreciate your assistance. You saved me ~$200!

    A similar situation on my '01 Silverado 4x4, 5.3L. Fan works, however speed intermittently changes at random times. More noticeable at the 4 or 5 settings, as though fan drops to 1 or 2, then kicks back up. From the experience with the Tahoe, I am guessing a bad blower and/or resistor. Am I on the right track? Replace both to solve issue?
    HouseCallAuto
    HouseCallAuto 9/20/2012
    Yes, the resistor or what is also called a blower motor control module.

    Glad it worked out for you.
    HouseCallAuto
    Chris_W 10/4/2012
    HCA - Hoping I can run another matter by you??? Had the trans on my 01 Silverado 4x4 inspected today by a local trans service mechanic. He came back that I have transfer case problems and he cannot give a formal estimate until he can open it up. His rough estimate was quite pricey; $1200-$1800. I know nothing about this; do I have other options? Is replacement possible/cheaper to do? Does this sound reasonable to you?

    Just looking for some advice on this one. Thanks.
    HouseCallAuto
    HouseCallAuto 10/4/2012
    Give me detailed story about what is happening that had you bring it to them. Do not let them do anything just yet or you will get caught in a catch 22.
    HouseCallAuto
    Chris_W 10/5/2012
    2 reasons for specific trans inspection. 1-never had 4x4 and wanted peace of mind that all was in good shape. do NOT want to have problem pulling boat out of water. 2-specifically when putting in reverse, there is a noticeable "clang". it goes easy, but can hear it. beyond that, some occassional noises from all over, but truck is 12 yrs old and 140k miles, so expect some of that. truck goes to work and back, boat ramp and back. little more. ideas?
  • HouseCallAuto
    HouseCallAuto 10/5/2012
    Chris, the #1 cause of no 4WD on most GM 4WD systems is the encoder motor that is attached to the outside of the transfer case. I want you to ask around and find someone who can read the transfer case codes for you for a small fee (like $25) or less or else start reading the details for all the various code readers in the $100 to $200 range for one that supports GM transfer case codes, anyway, bottom line is get me a fault code so I can continue and get your car out of that 1200 to 1800 place because your cause could simply be the encoder motor which you can replace yourself easily for under $200.
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    HouseCallAuto
    Chris_W 10/5/2012
    I will make some calls this afternoon and see what I can find out. For the record, 4WD seems to work fine. We have used it to pull our boat out of water once since we bought it and it worked great. Thanks for your advice.
    HouseCallAuto
    HouseCallAuto 10/5/2012
    I misunderstood your details. I thought that you meant by saying that you *never had 4WD* I took that as a different meaning. That changes everything. I still say do not have 1200 to 1800 in repairs done to transfer case without a clear explanation of what they want to do and why. What problem are they overcoming by doing this work? Maintenance does not cost 1200 to 1800, a major repair would cost that much.
    HouseCallAuto
    Chris_W 10/6/2012
    My apologies... I have never owned 4WD prior to this truck. Thanks for clearing that up. I will talk with them more to better understand what/why... And will seek a 2nd opinion.

    Thanks again for your time. I really appreciate it.
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