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Blower doesn't change from Defrost to Floor or Dash

10-26-2005, 12:00 AM
Hi all, I'm new to the message board thing, and have been reading for about a week now.. and decided to join. I can not find an answer to my question.

I have a 2001 Astro, I'm trying to sell. I had the transmission replaced last February, April Bought new truck, van sat all summer. I showed this 2 weeks ago (for the first time)
The blower motor would not change from defrost to the floor and/or to the vents in the dash. Also, all the speeds did work but when changing from the defrost to floor or where ever the motor did not get louder or push any more air that is normal when using the "MAX" A/C setting.
Not sure what to do. I've been looking and it seems maybe I have a vacuum leak, or a resistor problem. All fuses are good...

Any help would be great ! ! Thanks for such a very useful site !


10-27-2005, 07:41 AM
Vacuum line leak- probably right in front of TBI unit on top of intake manifold- pull out air cleaner housing assembly-(from under hood- no need to pull off dog house cover) look for black plastic vacuum line- it is most likely broken in two- from heat aging- got brittle and cracked- have seen numerous ones do this-- this is the source of vacuum that drives all your plenum doors inside- and without vacuum- the system defaults to defrost for safety in winter driving- other than that - check vacuum lone at your reservoir ball- under blower motor module- next to frame rail on passenger side. repair any vacuum leaks by cutting out frail areas- then use rubber tubing to splice over plastic line- no need to clamp anywhere- since it is vacuum you are dealing is an easy fix if you know what to look for.......

11-04-2005, 12:57 PM
brcidd got it right. Thanks. I just repaired the heater & a/c controller on my 2001 Chevy Astro and have some more details for all those who might need it. This is probably the same thing that will fix many other years as well.

Note that I replaced the entire vacuum hose and did not try to repair the section that was broken. Because it's so difficult to get to this hose to fix it, I just replaced it. Besides, the whole thing was brittle and may have soon broken somewhere else.

The bad hose was the vacuum supply line that brcidd said is in front of the throttle body. It's black and runs from a tap on the PVC valve to a T connector in the front of the engine compartment, passenger side, by the A/C fittings. Getting to it wasn't easy and required removal of the interior engine cover. Here are the details:

Remove the 90 degree vacuum hose connector off the T connector in the engine compartment.

Remove the top of the air filter assembly (i.e., doghouse). Loosen the large air intake hose clamp, disconnect the electrical connector to that assembly and remove the whole assembly.

Remove the rest of the air filter assembly. It's in rubber grommets on top of the radiator housing and pops right out. (I couldn't get the whole air filter assembly out without taking off the doghouse.)

Remove the glovebox dashboard assembly inside the car. To get it out, pop out the two plastic button inserts that cover the torx screws - one on each side towards the top of the moulding by the driver's right and passenger's left knees. At the bottom of the moulding are two 1/2" hex nuts that need to be removed. Then the moulding pops out of the dash. Disconnect the CD player and wiring harness connectors.

Remove the air duct to the rear. It's under the glove box assembly and pops right out. Take care to disconnect the flex tubing on the driver side of the duct.

Remove the engine cover. There are two bolts with screwdriver slots towards the top of the cover - one on left and one on right. The best way to do this is to use a real long (---) screwdriver. 18" will work fine. Then there are two brackets on the bottom with 1/2" hex bolts.

It's tight in there and I couldn't get the engine cover out, but could move it around enough to get at the PVC valve and vacuum line.

Remove the PVC valve (1/4 turn CCW pops it out). Pull the rubber 90 degree vacuum hose connector off the PVC valve connector.

You can reuse the rubber L hose connectors, but you need to get the old hose out. It takes some effort. My PVC side was broken at the rubber connector and I had to use a drill to get the plastic tubing out.

I bought 3' of 1/8" plastic tubing at Auto Zone, and used it as the replacement. It fit perfectly and was a bit longer. I didn't cut it though and instead ran it a little higher up and away from the engine.

If you have trouble running the new hose from the PVC valve to the engine compartment, you might have to move the throttle duct out of the way. To do that, you need to remove one wingnut that's on top of the rear of the TB and accessible from the inside.

After you have the hose in place and connected at both ends, just reassemble everything in opposite order. Remember to plug the big fat PVC hose back into the valve cover.

Good luck.

11-04-2005, 01:16 PM
Great- good to know you can win one once in awhile!! By "doghouse" I was referring to the engine cover- inside the van- it is shapped like a doghouse- has been casually called that since the inception of vans...Glad to know you were able to fix it proper- most I tell this to give up too easily....

11-04-2005, 02:12 PM
Thanks for the terminology description. Yes, had to remove the "doghouse" to get at the PVC side of the hose. It was a lot of work to replace a $5 part, but I bet I saved a lot of money. Can't image a shop doing it right for less than a hundred.

Thanks again for your post. If it wasn't there to get me started, I would have kept driving around with defrost only. Now I've got that sweet A/C blowin' in my face.

12-16-2005, 02:05 PM
Thanks for all of the help. I would not have been so fortunate to find the vac leak without your help. FYI, my problem was at the harness as it goes thru the firewall, behind the battery on the 1995 Astro with V6 engine. Battery acid had destroyed both vac hoses in that harness. All I needed was to patch the hoses using some spare Rubber Gas Line or Vac hose(?) I had on hand with an Inside Diameter that was close enough to provide a snug fit to the outside diameter of the damaged vac lines.

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