Jump to content

Blower motor on high speed and no air flow out of vents

redsled2007

By redsled2007
in Ask A GM Technician

Recommended Posts

redsled2007 Enthusiast

redsled2007

Posted
Posted

I have a 2007 Sierra Denali with climate control. My problem is after about 45 minutes of driving, with the air conditioner selected. the blower motor speeds up like it's trying to catch up. Then I notice that there is no air flow coming out of the vents. I try manually selecting vent, floor, or defroster. I here them change, but no air flow out anything.

If I turn off the truck for about 15 minutes then start driving again, everything is ok for about 45 minutes, then it starts all over again.

Bad Bowtie2 Enthusiast

Bad Bowtie2

Posted
Posted

Call your local GM service Dept with your VIN#. You may qualify for an extended campaign on the blower motor resistor & pigtail connector....

redsled2007 Enthusiast

redsled2007

Posted
  • Author
Posted

The air flow issue is like a door has closed some where.

The whole dash was replaced a couple of months ago due to cracking by the air bag along with the climate control unit (lights burned out).

The reason I say it's like a door, when I restart after the air flow problem, the blower starts up with no air flow for about 1 second, then air flow.

The pass side of the controller does not shut off the pass side like it used to.

Yes, I took it back to the dealer who did the dash and they said the controller would not do this. BUT, they were aware of this issue and could "Fix" the problem with a modified program from GM.

It would ONLY cost me $175 to reprogram the BCM , and it WAS NOT covered by my warranty!!

Before I shell out $175 on something that I think should be under my warranty, I'd like to here from some other folks.

redsled2007 Enthusiast

redsled2007

Posted
  • Author
Posted

If you can hear the blower motor running, it is possible that if the humidity is high, the evaporator core may be icing up and blocking airflow. With the system off it gets a chance to thaw out and the blockage melts away. This can be caused by overcharging the system. Check this thread out http://www.gm-trucks.com/forums/topic/117238-air-conditioning-advice/

You may be on to it. It happened again yesterday, so I stopped the truck and checked the evaporator cooler and seen that it was covered in frost about a 1/4" thick along with all the lines leading up to it and out.

Unit has never been serviced since new, so I'm thinking a little low or the accumulator pressure switch is bad. (No problems with cooling temp)

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Chuck FB
      Oil Consumption

      By Chuck FB · Posted

      Through the years it hasn't been my typical method as I tried to drop oil on an engine that was hot from having been worked, however that was not always practical and had to fire up a unit and let it warm up reasonably well and drop the oil when I had the time to do it but am referring to not only vehicles but a variety of farm equipment and highway tractors etc. However on a vehicle where one is crawling under it and the exhaust is nearby to ones body and if wanting to pull the plug without danger of being hit with boiling hot oil or attempting to remove a HOT oil filter, its sure safer and easier to not have everything smoking hot and can remove the filter right away when under the vehicle and let it all drain. Of course its not the end of the world if a bit of oil stays in the engine that might have eventually found its way out, I like to get out as much as possible but any oil changes that take place in shops would rarely be sitting around for very long at all before the plug is thrown back in and filter slapped on and oil poured in and sent out the door quick like. There would be very little time spent ( assuming they even did it ) in starting the engine with oil to fill the filter, then waiting to verify the level on the stick. A good reason to check ones oil level shortly after a shop changed the oil on a vehicle just to make sure its correct and to look under for any oil around the drain plug or filter. 
    • CPhelps
      4 Wheel Drive System

      By CPhelps · Posted

      Cool to see another Vermonter!
    • diyer2
      Winter Returned

      By diyer2 · Posted

      To many wildfires.
    • diyer2
      Oil Consumption

      By diyer2 · Posted

      I have changed oil and filter for years by starting a cold engine to warm oil up, let it run 5-10 minutes depending on temperature. Drain until it starts dripping, refill with quantity from owners manual or get it close.   
    • Chuck FB
      Fluid Change Questions

      By Chuck FB · Posted

      I changed the factory fill oil in the rear diff of my truck for the first time today and the miles is close to 9000 on the truck. There was a lot of fines on the magnet, a very thick layer but working it through my fingers it all felt like mush and as most know it appears like graphite, so no surprise chunks anyway. Certainly was time to do it from my thinking and could have been done sooner but the oil didn't look awful but sure wasn't new looking and never expected it to either. I did use some solvent to help me clean out the bottom area of the axle housing, just get any other stuff settled at the bottom washed and wiped out of the housing for the bit of effort it takes. I used Amsoil Severe Gear 75W90 in the easy packs to try out what they are like and I used up 4 packs and didn't spill much at all in the process but did take all four of the packs and go to the work bench and emptied them into a measuring container and there certainly was some in them that added up to something, then poured that into one of the easy packs and squirted in what I could get out of it. I would say the level is within 1/8th of an inch of being level with the threads at the fill plug so just the perfect amount. Once again, more than what GM says the fill volume is but computes with what others are adding to their rear diffs as well. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...