Recently my air stopped blowing through my vents and I'm not sure why. If I put it on defrost/feet mode it will blow throughout the whole vehicle but if I put it on any other setting then it doesn't blow any air hot or cold. :( Is something plugging my vents? Or something disconnected?

Any ideas?

 

Could be a vaccum leak to the HVAC.

Look for the round black ball-shaped reservoir. Inspect it for cracks.

Check the entire length of the vaccum line that goes into the ball (I think the line is grey), as well as the fitting on the ball that the vaccum hose connects to.

If you don't find any problems there, look for similar lines problems behind the glovebox door. You can open it further to see by pressing in the sides to release the tabs.

The default setting is Defrost, so see if THAT is where all your air is going. If so, you do have a vaccum leak.

 

I will check with that and get back to you.

 

check the fan speed control module (think that is the name) I had similar problems and it turned out to be that. It will be right under the blower motor, there should be a plug with about 6 wires running to it.

Take out the screws and pull it out to check if its burnt out anywhere.

 

Have no idea where that's at. I'm auto newbie :x

Please elaborate :o

 

I took some pictures.

The first pic. shows the area that you need to look, and in the others I have a ruler pointing at the part you need to take out and check for damage. Mine is covered in electrical tape because the plug shorted out so I had ot replace the plug. You should check for that also.










Another thing that you should check is where the vacuum lines enter the reservoir behind the fender and where the same line connects to a T and branches off to other lines. It has some rubber vacuum hose that is used to couple the plastic lines to the reservoir and the T connector, these will rot and have small cracks in them, so you may have to bend them and/or look close to see the cracks.

The t connection is either under the air box or the radiator overflow tank I dont remember.

To get to the reservoir behind the fender, I removed just enough screws on the plastic fenderwell to bend it back to where I could get to it.




(ignore my dirty engine bay)

 

When you say "doesnt blow" does that mean the fan is not spinning? Or is it no air coming threw any vents.

 

No air comming through any vents. I know the fan is spinning and the air is pumping but it's not comming out like its clogged or something is loose.

 

bah i wish it was warm enough to use the A/C here lol

 

Do a search for 'Blend Door Actuator'
I've read several posts in the past few months where people have had issues with it.

 

The blend door and BDA only affect air temperature. Air flow and direction are controlled by vacuum.

I agree with Earl's approach to the problem.

 

I agree with Joe, and Earl. It isn't the fan speed control module (the correct name is blower resistor assembly) because the fan is working on defrost/feet mode. If the resistor assembly was bad, the fan would only blow on high (or not at all) on any mode........

 

Thanks all! I will look into it and keep you updated.

 

I had both of those problems and I ended up having a vac. leak and the blower resistor was melted and packed with mud.

I still think he should check the vac lines I was talking about. Mine did the same thing and those were the problem areas.

 

I would check under the glove box area for an unplugged vac lines. I have had this happen from dumb people riding shot gun.

Also verify the vacuum harness is plugged 100 percent to the selector switch. After that a vacuum gauge maybe needed to verify your getting a supply to the selector.

 

This has been fixed.
It was a vacuum leak in the rubber hose connecting to the black sphere. Cut it off and plugged it back in and I get full air outta my vents :)

woot.

Thanks R-F!

 

Hey all,

I am having a similar problem, only my vents work fine until I go above 3k. That is all fine and dandy, except it has been 95 degrees plus and most of my drive to work is highway and with the 4.10 gears, that doesn't get me much air flow in my face where I want it.

I have checked all the connections behind the dash and any vacuum lines I can find in the engine bay and all look good. However, I crawled under the truck to check the VPH lines and they look like crap, on both sides.

I want to make sure I am looking at the correct line though. I think it is the rubber hose coming off of the metal tube that takes a 90 degree. I just recently changed both front hubs, so I know which are the ABS wheel speed sensors and which are the brake hoses. Which by process of elimination leaves only the VPH line, correct?

Does anybody know what ID that line is? I may stop by the O'Reilly's on the way home and see what my bulk options are. They both look like they need to be replaced all the way to the connector piece. Do I have any other options other than rubber? Granted these are probably original and at 124k, whatever I get shoudl outlast the truck at this point.

If this fix doesn't work, I guess I going to have to dig for the reservoir under the air box/ radiator overflow tank.

Any input is greatly appreciated!

 

I replaced those hoses a few years back on my '98. The type of replacement hose I used was Gates 3/16" (4.8mm) SAE 30R7. I think I got it from Napa. It's a fuel line hose and therefore is of solid construction and resistent to kinking. The hose(s) fit snug enough on the metal tube ends, but I also used some rubber stretch tape to seal the connections further.

FWIW, from those metal tubes and the rubber hoses you are replacing, the lines then turn into plastic hose before they get to the PVH solenoid. The same type of plastic hose(s) also run from the PVH solenoid to the vacuum reservoir, and then from the vacuum reservoir up the intake manifold.

 

Well, I pulled the RH hose from the metal pipe to the frame connection and while it was brittle as all get-out, it isn't the root of my problem.

With the hose disconnected and off the truck, I went for a short drive and still have the problem and my vents work fine without it in place, well until 3rd gear. Once in 3rd gear, it switches from the upper vent to the defrost and doesn't' come back until I begin braking.

I'm still going to replace both those VPH hoses, but where else can I go to look? The connector mentioned above looks to be fine, not burnt out. Can the selector switch go bad and cause something like this? There are so many vacuum lines under the hood, I could be there all day tracing hoses.

Thanks for the hose size Rockledge! I went to O'Reily's thinking 3/8" and when I saw how large that was, I ended up with some 1/4" hose. Still a tad too big to fit snugly. But at only $0.89 a foot, it's no big loss. Going to go back tomorrow with the line off the truck and hope they have a 3/16".

Stupid local NAPA closes at 5:30 and when I get off of work at 5, I get there about 5:33 and they are closed. I swear I wonder how that place makes any $$.

Any other ideas?

 

Have you pulled off the passenger front wheel and removed the mud guard to gain access to the vacuum reservoir yet?

 

Ok, well after I replaced both hoses to the hubs and drove a little bit, the problem has gone away. Been driving it for a little over a week, and knock on wood, everything is golden.

I ended up getting the hose at Advanced Auto, 3/16" fuel line, cost about $1.20 per foot. I bought 6 feet (3 per side) and ended up using just a little over 2 feet per side. The only problems I ran into were the new hose wouldn't fit into the screw-on clamp on the back of the knuckle and the stupid clip on top of the frame wouldn't give up the hose. Nothing a few strategically placed zip-ties couldn't fix though.

4wd seems to lock-in better than it has too!

If I do look at the vacuum reservoir, what should I look for? I should probably still investigate it.

 

sweet