Defrost not working after warmup
#1
Defrost not working after warmup
I have searched and can't seem to find this exact problem.
2000 blazer lt auto climate
On the first start of the day and if it's cold out I can control the selector to any place I want, floor defrost face. After the vehicle warms up I hear a air hiss and all the heat comes through the front vents. Even if the selector is at defrost or feet. What could this be? Thanks.
2000 blazer lt auto climate
On the first start of the day and if it's cold out I can control the selector to any place I want, floor defrost face. After the vehicle warms up I hear a air hiss and all the heat comes through the front vents. Even if the selector is at defrost or feet. What could this be? Thanks.
#2
The hiss is from the selector switch leaking. Will likely need to replace the switch, but may be just a loose connection for when it gets warmed-up.
Pull the trim panel off and take a look at.
Good luck.
Pull the trim panel off and take a look at.
Good luck.
#3
The selector switch? I have pulled out the hvac panel and looked it over. Nothing out of the ordinary.
#5
No I haven't had a chance to do anything to it yet but want to this weekend. So unhook the hvac panel and run the vehicle? What am I looking for?
#8
Okay watched the video and have an understanding of the problem now.....air flow is switching from defrost to dash.
I always thought that defrost was the default safety position...so if vaccum was lost, air flow would be direct to defrost. So doubt this is a vacuum leak.
Wondering if the controller circuit is failing once it gets warmed-up and just switches air flow. Before replacing the HVAC head unit, I would crefully take it apart and check the solder connections for corrosion and reflow every solder joint on the circuit board. I have solved many problems doing this as all those temp cycles crack solder joints. Be sure to use a soldering iron, not a gun.
Let me know what you do.
I always thought that defrost was the default safety position...so if vaccum was lost, air flow would be direct to defrost. So doubt this is a vacuum leak.
Wondering if the controller circuit is failing once it gets warmed-up and just switches air flow. Before replacing the HVAC head unit, I would crefully take it apart and check the solder connections for corrosion and reflow every solder joint on the circuit board. I have solved many problems doing this as all those temp cycles crack solder joints. Be sure to use a soldering iron, not a gun.
Let me know what you do.