blower control problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mekdad · 08-06-2008, 05:57 PM

1996 s10 blazer my a/c and heat only blows through the defrost and floor at the same time does not even try to blow Through one or the other separately and not Through the dash at all.Any ideas what would cause this? I have replaced the control switch with a used one and no change.

54 jimmy · 08-06-2008, 06:59 PM

could be a vacume actuator on the heater box behind the dash or a vacume line is pinched mabye even fallen off.

gchemist · 08-08-2008, 05:29 PM

Check the vacuum hose behind the air intake over the throttle body. The hose connects to a vacuum resevior to move vents. I had the same problem. I replaced hose because it would fall off occasionally.

mekdad · 08-12-2008, 10:00 AM

thanks for the replys.I checked all of the lines I could get to and all seems fine.Is there a good way to get to the actuator on top of the heater box?I think thats my problem.

gchemist · 08-17-2008, 08:51 PM

You can pull the bezel and check behind the switch for vaccuum.

68C15 · 08-19-2008, 08:05 AM

it sounds like you have a problem with the lower mode door or the actuator. it has a brown and a black hose. it is a dual action diaphram.
wait a minute, you said you catn switch from defrost to vent either? the vaccum flows from the manifold (drivers side) to the ball thing mounted to the hood. then to the dash. start tracing the hose under hood using the emissions sticker as a guide.

mekdad · 08-19-2008, 08:48 AM

I have vac to the switch and it is stuck on defrost and floor at the same time.

Slammed70 · 08-20-2008, 09:05 PM

Dont feel bad, when my fan control is set on the "two" setting my truck clicks.

08-06-2008, 05:57 PM	#1
mekdad Registered User Join Date: May 2008 Location: Filer, Idaho Posts: 416	blower control problems 1996 s10 blazer my a/c and heat only blows through the defrost and floor at the same time does not even try to blow Through one or the other separately and not Through the dash at all.Any ideas what would cause this? I have replaced the control switch with a used one and no change. __________________ you never know what you can do until you have to undo something you have done!

08-06-2008, 06:59 PM	#2
54 jimmy Registered User Join Date: Oct 2007 Location: pittston,PA Posts: 1,183	Re: blower control problems could be a vacume actuator on the heater box behind the dash or a vacume line is pinched mabye even fallen off. __________________ There is nothing you can't fix with a BFH or a FIRE WRENCH. 1997 chevy k1500 ext cab z71 (daily driver) sold 1996 chevy k1500 reg cab 4x4(daily driver)totaled 2008jeep patriot (wife's daily driver 2008 chevy 1500 ext cab 4x4 sold 2011 chevy 1500 crew cab ltz (daily driver) 1996 chevy 1500 reg cab 4x4 project sold 2006 pontiac grand prix gxp (daily work commuter)

08-08-2008, 05:29 PM	#3
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: blower control problems Check the vacuum hose behind the air intake over the throttle body. The hose connects to a vacuum resevior to move vents. I had the same problem. I replaced hose because it would fall off occasionally.

08-12-2008, 10:00 AM	#4
mekdad Registered User Join Date: May 2008 Location: Filer, Idaho Posts: 416	Re: blower control problems thanks for the replys.I checked all of the lines I could get to and all seems fine.Is there a good way to get to the actuator on top of the heater box?I think thats my problem. __________________ you never know what you can do until you have to undo something you have done!

08-17-2008, 08:51 PM	#5
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: blower control problems You can pull the bezel and check behind the switch for vaccuum.

08-19-2008, 08:05 AM	#6
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: blower control problems it sounds like you have a problem with the lower mode door or the actuator. it has a brown and a black hose. it is a dual action diaphram. wait a minute, you said you catn switch from defrost to vent either? the vaccum flows from the manifold (drivers side) to the ball thing mounted to the hood. then to the dash. start tracing the hose under hood using the emissions sticker as a guide.

08-19-2008, 08:48 AM	#7
mekdad Registered User Join Date: May 2008 Location: Filer, Idaho Posts: 416	Re: blower control problems I have vac to the switch and it is stuck on defrost and floor at the same time. __________________ you never know what you can do until you have to undo something you have done!



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