defrost quit working

moldmaker · 12-17-2007, 09:03 AM

defrost went out on me this morning. Just quit blowing all together. I was hoping someone could give me an idea of where to start checking. Thanks in advace.

mudseeker · 12-17-2007, 09:34 AM

do the other settings work?
check your fuse to begin with.

moldmaker · 12-17-2007, 10:06 AM

yep. the vents and the floor work. just the defrost.

Hayden · 12-17-2007, 02:56 PM

It'd be nice to know what vehicle it is

nordy · 12-17-2007, 03:15 PM

Most likley a vacuum leak.

moldmaker · 12-18-2007, 05:38 AM

sorry bout that. it's a 2000 silverado ext. Z71. just got in it this morning and found the heat quit working. Yes. the truck was fully warmed up. Checked the heat/ac fuse. It was good. No water on pass. floorboard from bad heater core. guess vacuum lines are next

mudseeker · 12-18-2007, 11:07 AM

does the blower still work and it just blows cold air?

moldmaker · 12-19-2007, 05:30 AM

i know you all will think i am retarded but i was messing with the recirculate button when it started blowning cold. switched it back over to fresh air and the heat works fine. still having a problem with the defrost though. The fan is blowing fine

1979_4x4_Plow · 12-19-2007, 01:42 PM

sounds like a vac contolled switch stopped working that directs the heat flow. i know that on one of my cars it has a auto temp control and if it stops working for floor and such that it is the electronic temp contol sensor that is inline on the heater core hose.

12-17-2007, 09:03 AM	#1
moldmaker Junior Member Join Date: Dec 2007 Location: mississippi Posts: 4	defrost quit working defrost went out on me this morning. Just quit blowing all together. I was hoping someone could give me an idea of where to start checking. Thanks in advace.

12-17-2007, 02:56 PM	#4
Hayden Senior Member Join Date: May 2006 Location: Bay City,Michigan Posts: 387	It'd be nice to know what vehicle it is __________________ There Is No Replacement For Displacement

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12-17-2007, 09:34 AM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	do the other settings work? check your fuse to begin with.

12-17-2007, 10:06 AM	#3
moldmaker Junior Member Join Date: Dec 2007 Location: mississippi Posts: 4	yep. the vents and the floor work. just the defrost.

12-17-2007, 03:15 PM	#5
nordy Junior Member Join Date: Oct 2007 Posts: 8	Most likley a vacuum leak.

12-18-2007, 05:38 AM	#6
moldmaker Junior Member Join Date: Dec 2007 Location: mississippi Posts: 4	sorry bout that. it's a 2000 silverado ext. Z71. just got in it this morning and found the heat quit working. Yes. the truck was fully warmed up. Checked the heat/ac fuse. It was good. No water on pass. floorboard from bad heater core. guess vacuum lines are next

12-18-2007, 11:07 AM	#7
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	does the blower still work and it just blows cold air?

12-19-2007, 05:30 AM	#8
moldmaker Junior Member Join Date: Dec 2007 Location: mississippi Posts: 4	i know you all will think i am retarded but i was messing with the recirculate button when it started blowning cold. switched it back over to fresh air and the heat works fine. still having a problem with the defrost though. The fan is blowing fine

12-19-2007, 01:42 PM	#9
1979_4x4_Plow Senior Member Join Date: Dec 2007 Posts: 98	sounds like a vac contolled switch stopped working that directs the heat flow. i know that on one of my cars it has a auto temp control and if it stops working for floor and such that it is the electronic temp contol sensor that is inline on the heater core hose.