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strange "Clicking" from pass side low dash

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by collinsperformance, Feb 20, 2007.

  1. collinsperformance

    collinsperformance New Member

    ok here is a strange one that started mid road trip. vehicle+ 1993 K1500 Suburban with the 350 /auto tranny/4x4 (do not think it is model suspecific) the suburban has 300990.90 miles and running great, but this last weekend we went on a 300 mile B-day road trip. after the 2/3 of the trip was compleated we stopped for dinner and when we started the burban after dinner it made a clicking sound from low behind the pass heaterbox (sounds like a relay cycling (it sped up last night) or a broken power antenni motor) it last for 30 seconds and now does it when you start the motor and turn off the key both times it will go for 30 seconds and stop. i can drive for any time after and there seems to be no performance issues. the cruse control works all wipers, windows work. we had this truck for 3 months and the only things i done so far was oil,filter and lube and replaced the back-up neautral switch on the steering column. the only thing that gone strang is last month the ac stopped getting the compressor signal so no AC (i was looking into why but the sons Bday trip was right in the middle. any ideas? would this be like the only thread i found the multi function switch? thanks..i am just learning this beast ....mike
  2. TrailLeadr

    TrailLeadr New Member 1000 Posts

    That's kind of an interesting one. There isn't really much down there besides the fan, the ECU, and a couple small modules. The flap that regulates the vents (floor, dash, defrost) is in the center of the dash, behind the two center vents.

    Any after market installations, like a remote starter, alarm, CD changer?
  3. collinsperformance

    collinsperformance New Member

    the only add in was a Locktronics but the was a the dealership and it is working fine. no other installs stock radio (am/fm does not work) and eq cassette...i got the ipod plugged into the cassette and works fine. i can not think of anything that gets power for the first 30 seconds the key is on and then again 30 seconds after the key is turned off. it is behind the heaterbox and the firewall. it is below the glovebox. it was a steady 1-2 clicks a second for 30 seconds but now it is 4-6 clicks for the same time every time the key is on and when turned off. it is very loud and the clicking can be felt thru the floor and dash but so much on the engine side of the firewall (can be heard but not as strong)..........it just started on Monday morning......mike
  4. unplugged

    unplugged New Member 1000 Posts

    Blend door motor/actuator

    Googled it cuz a friend of mine has a GMC Jimmy with the same problem. It looks like the issue is a "blend door actuator" read on:

    From: Yahoo Answers
    I have a 1994 Chevy C-1500 that is making a clicking sound behind the glove box area,what might that be?

    The clicking starts when I crank the truck up and last about 15-20 seconds.I hear the same clicking when I turn the truck off and it lasts about the same time.Like I said it is coming from behind the glove box above the heater core.The heater core has not shown me signs of it being bad,no leaking,and no foggy windows.
    2 months ago - 6 answers


    Answer #1


    I've got a 91' Chevy 2500, and I've looked into it in the past.

    What's happening is the heater controls are run by little electric motors that open and close vent doors.

    When these little motors reach their limit as far as opening, or closing these doors, the "ratchet" on a limit spring so the motor won't burn up.

    All that's happening, is the motor is trying to open or close a vent that has already reached its limit of movement.

    Don't sweat it. It's kind of normal.

    Answer#2
    Best Answer - Chosen By Voters


    "mr know it all " was close but, not quite right.
    The prolblem is a blend door motor, not a relay.........
    This is a common problem.
    I've replaced several....
  5. 84fiero123

    84fiero123 New Member Platinum Contributor 1000 Posts

    I vote for the electric ant. if it has one.
  6. collinsperformance

    collinsperformance New Member

    this suburban never had a power antenni. i research more on the blend door. if i pull the ac fuse this should stop the sound to verify this is the issue? and if this is the case just put the door back in the normal sweep?. thanks i new to this new car stuff. i used to the older vehicles...mike
    1 person likes this.
  7. collinsperformance

    collinsperformance New Member

    ok- here is todays findings and a huge thank you for helping me put my mind to ease. the sound is the blend door. I got in the suburban this morning and as i started the truck the "clicking: started and i hit the "Max" button and it stopped for a few seconds (it then seemed to move and have a different pitch) then i hit the "Max" button agin and it go away and return after a few seconds. so next step is to remove and fix or replace the parts. i post what i find but it will not happen till this weekend.......again thank you...mike
    1 person likes this.
  8. collinsperformance

    collinsperformance New Member

    i went to PNP univerisity this weekend and get some schooling on where and how to swap this part. It is a pain to get to, but i going to try. is the blend door motor the same same as the reare blend door motor and the other door motor on the heater/AC? I was able to get up there and unplug the "Fresh/recycle" door motor plug and the clicking is gone. so as soon as we get a few dry days i try and remove the 2 screws on the motor and swap it out.......thanks for the help.......mike
    1 person likes this.
  9. unplugged

    unplugged New Member 1000 Posts

    Take some pics if you can. Always nice to have as much info as possible on a repair. It will help those who follow in your footsteps.:biggrin:
  10. collinsperformance

    collinsperformance New Member

    these may not be the best pictures but the space is small. the motor has a plug that you need to press a tab near the top of the connector and the wires will come right out. here is the motor for the fresh or recycle door. it is located between the blower motor housing and air transport dristribution box. (iff you are sitting in the pass side seat look down below the glove box and on the roght you see a round black and to the left a black square box. inbetween these is sorta a upside down "V" notch this part is in there. it is bolted to the blower motor housing.
    [​IMG]

    here is the new replacement motor. this is the working side or the part that opens and closes the mix door.
    [​IMG]
    the small 7MM screws at at the top and bottom holes the other is a molded pin on the housing.
    [​IMG]
    i hope this helps. you can get in the space with a 1/4" drive and socket or a flexable driver. it is so good to not hear the clicking at the start and end of my trip. this is an easy fix but it can be very frustrating since it is a very cramped space and i not found any books anywhere to show an easier way of replacing this part. again thank you for helping me locate this issue.......mike
    1 person likes this.

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