I have a 2005 Sierra Diesel Duramax truck, I had to replace both batteries, everything was working just fine but now the AC/Heart blower is only blowing air out of the defrost vents, none of the dash vents have any air blowing out. Is there some kind of a reset I need to do or is there a safety feature that got engaged from replacing the batteries and how do I reset the blower?

SOURCE: Dash vents will not blow air. Defroster and floor vents blow fine.

Is it a new vehicle? I had a new vehicle that had the same problem. Answer was that the holes weren't punched out of the vent.

Colin Stickland

• 22516 Answers
• Posted on May 30, 2009

SOURCE: a/c and heater only blow air out of defrost

either a vacumn pipe is broken or the ends split so its not passing a vacumn to open the flaps,where they are and how to get to them i cant help because i have never worked on one as they are not here in spain.check the engine end first though .Look for some small rubber pipes running from the inlet manifold

SOURCE: I need to replace the fuel filter on my 2003 GMC

ITS A SPIN ON FILTER, YOU NEED TO DISCONNECT THE WATER SENSOR ON THE BOTTOM OF THE FILTER, THEN USING A STRAP FILTER WRENCH LOOSEN THE FILTER AND SPIN IT OFF.

CHECK THE FILTER HOUSING TO BE SURE THE INNER FILTER SEAL ISN'T ON THE HOUSING AND CAME OFF WITH THE FILTER.

REMOVE THE WATER LEVEL SENSOR AND DISCARD THE SEAL.

INSTALL THE WATER LEVEL SENSOR ON THE NEW FILTER. USING A LITTLE GREASE ON THE INNER FILTER SEAL AND ON THE OUTER O-RING TO HOLD IT IN PLACE, SPIN ON THE NEW FILTER.

OPEN THE VENT ON THE UPPER SIDE OF THE FILTER HOUSING. PUSH DOWN ON THE HAND PUMP QUICKLY UNTIL THE FUEL IS COMING OUT OF THE VENT. CLOSE THE VENT AND PUMP THE FILTER PUMP UNTIL IT FEELS SOLID. AT THIS POINT START THE ENGINE. IF IT STALLS PUMP IT UP AGAIN AND RESTART THE ENGINE. IF YOU HAVE AN ASSISTANT THEY CAN PUMP THE FILTER PUMP WHILE THE ENGINE IS RUNNING AND QUIT WHEN YOU FEEL THE ENGINE IS NOT GOING TO STALL. ABOUT 10 TO 15 SECONDS USUALLY WORKS.

CHECK FOR LEAKS.

BEFORE STARTING THE ENGINE USE BRAKE WASH TO REMOVE THE FUEL SPILLED DURING THE FILTER REPLACEMENT. ALLOW IT TO DRY BEFORE STARTING THE ENGINE.

RATE ME PLEASE.

SOURCE: I replaced heater core in 1999 gmc sierra 1500 5.3

no,, the system works from a vacuum and has to be worked on in a service garage. sorry about the bad news...

Ronny Bennett Sr.

• 6988 Answers
• Posted on Jul 17, 2010

SOURCE: My AC and heat will only blow out of my defrost

Check the actuator motor under the dash,you may not be able to reach it,there is one under the dash on the bottom of the blower box,this is not the one,this one is the temp door actuator,you need to find the directional door actuator,follow the clicking noise,this is the one that needs attention,the door is stuck,or the actuator motor is bad.If this was at all helpful,please rate.