Blower cutting off when going up hill.

[ablaize]

Hey guys. I am new here and think I've already found a solution to one of the problems I have with my '99 Astro van so I'm already a fan of the sight. I'm hoping that someone might be able to point me in the right direction for this 2 part issue regarding my climate controls.

The first part of the issue is that my blower quit working on the highest setting. Works fine on lower 3, just not on high. It used to work on the high setting then one day it just quit.

The 2nd part of the issue and it could be related is that many times when driving up hill, if there is any steepness to the hill, the blower will stop altogether until I crest the hill. At that point air will begin to flow again from the vents. The vents stop blowing whether the van downshifts or not. It seems to happen on just about any and every hill and at various speeds from 15 - 70mph.

Any suggestions as to what might one or both of these issues with the vent blower?

thanks in advance.

[chevymaher]

Under the hood there a vacuum valve.Engine looses vacuum under acceleration. Diaphragms that control vents loose vacuum they go to static setting.You can go buy the factory replacement for what ever it cost.Or pay 2 bucks for a aquarium air bubbler one way check valve and put it in the vacuum line.I can stand on mine till it wont go any faster my air stays right where I set it.Mine has lasted 8 yrs.
Blower moter speeds is a different problem entirely.Electrical in nature.Phantom is the man to field that question for you.

[unrreal]

the reason why the fan doesnt operate at high speed is because one of the connectors in your a/c control switch is burned out take a look at this for reference : viewtopic.php?f=34&t=12985 look at the pic, oh and they are a bit of a pain to fix since you have to take the washer fluid and coolant reservoirs out to get to it, but after that is an easy fix, as far as losing air on acceleration is gonna be because you either dont have or have hooked up wrong the one way valve on the vacuum line, in the engine compartment on the pass. side there is a 3-way vacuum splitter with a built in one way valve if the lines are hooked on the wrong spot you will lose all your vacuum when accelerating or climbing hill ( which puts more strain on the engine) i will get some pics and post them tonight to help you out..

ok here are the pics:
this first one is the vacuum check valve located behind the evaporator (the important one is the black piece on the valve that is the side that has to go over to the engine to prevent vacuum loss)

and this is what the valve looks like

vacuum valve

vacuum check valve 2.jpg (32.64 KiB) Viewed 1289 times

the next ones is where the a/c control switch is:

right behind the reservoirs

[ablaize]

Thanks for the responses guys. Both were very helpful, especially the pics when it came to finding the parts in question. I found the wiring harness for the blower motor, it didn't look burned out, but seemed a little corroded...so being the newb that I am, I took a wire brush to it to clean it. Apparently, this is the wrong approach as the brush created a connection between the the notches and sparked and now it does look burned out. I guess I'll be looking for a replacement there as I still have no high fan speed. Just wanted to say thanks again for taking the time to help.

[Jasen]

After your learning curve with the wire brush we've all been there in some form or another
You still have the 3 lower speeds and still no high speed?
Wondering if it's the blower resistor.

[ablaize]

My thinking at this point is that even if the brush cleaned the corrosion, the connector now looks pretty much fried. This was a live and learn moment...I'm sure many more to come as I concentrate more on my other issue which looks like either a worn out ignition coil/distributor combo or fuel pump...I wish I didn't like this van so much.

[smokinjoe]

I had this exact problem last year. I removed and cleaned the dash fan switch, cleaned the connector (no wire brush) and then replaced the blower. I shoulda asked here cuz I never checked the vacuum jammy. It works fine now so maybe I fixed it accidently.

[edlps]

a tip when replacing the blower motor, once the motor is loose and ready to pull out youll have to remove the plastic fan before the motor will come out fully and youll have to reverse doing that on the install, motor in and then attach plastic fan

ed

[unrreal]

Thanks for the responses guys. Both were very helpful, especially the pics when it came to finding the parts in question.

you're welcome glad to help anytime, this is one of the first things i ever fixed on my van when i got it, took me a while to figure out the vacuum lines since they where all broken when i got the van...

[Lookout1979]

I do have a question, maybe a stupid one, but still a question - why are these parts failing on later model vans? The 1996 Ram I had (which was treated VERY badly as a work truck) never had vac issues, A/C issues, blower moter issues etc, what is the deal here?

[Jasen]

I feel a large part of these problems are do to the tight/cramped motor bay. Not much room for air to move in there and keep things cool compared to most anything else.

[chevymaher]

I feel a large part of these problems are do to the tight/cramped motor bay. Not much room for air to move in there and keep things cool compared to most anything else.

The original engine shroud for the engine fan traps heat in the engine compartment. I was frying things every summer like clockwork. Alt, was cooking the insulation off the windings. Open the hood in the summer it was painfully hot checking the oil. Touch the alternator it would raise a blister.
Since I put the electric fan underhood temps dropped and I not exaggerating hundreds of degrees.

[Lookout1979]

Guess that is true, the truck had a 318 in it and it was nothing BUT room under the hood... just couldn't figure out why everything worked on it accessory wise, used and abused to it's max, and the van which was kept in very good shape, everything goes crazy in that department. I will admit, even without my High Blower setting working, just turn on the rear A/C up to max and she gets ice cold very fast w/ A/C on 3rd setting... no complaints and not gonna worry about it anymore i'll get around to it when I can. Right now it's time to fight w/ the lawnmowers. As for my engine temp however, it is still hovering around 180 after the new radiator thank god.

[chevymaher]

Right now it's time to fight w/ the lawnmowers.

OMG grass growing sticks and leaves in the yard from the winter. I just got the wife to accept no yardwork untill the van done. The neibors will get over it. Or I would be starting lawn mowers and weedwhackers now to.

[Lumpy]

Oh c'mon Maher. You could mow the lawn while you're waiting for your gasket cement to dry.


Lump

[Lookout1979]

Right now it's time to fight w/ the lawnmowers.

OMG grass growing sticks and leaves in the yard from the winter. I just got the wife to accept no yardwork untill the van done. The neibors will get over it. Or I would be starting lawn mowers and weedwhackers now to.

Well a sunburn later, i've got the backyard back to golf course status, the poor pushmower has had it tho, had to duct tape the throttle on wide open just to keep it going - it's revving like crazy blowing smoke everywhere, but, got it done Just waiting on the EPA to knock on the door now

[2000gmcsafari]

Can you post details on the "aquarium air bubbler"? My 2000 Safari van is having the same problem with the blower shutting off when climbing a hill. It has recently gotten worse where it shuts off randomly and comes back on.

Thanks,

[chevymaher]

Can you post details on the "aquarium air bubbler"? My 2000 Safari van is having the same problem with the blower shutting off when climbing a hill. It has recently gotten worse where it shuts off randomly and comes back on.

Thanks,

Your vents are operated by vacuum from the engine. There is a valve which traps the vacuum in the system. It is a one way flow check valve. When you accelerate Engine vacuum drops. If the check valve leaks then the vacuum operated doors in the dash loose vacuum and return to their static/neutral position. Floor or defrost depending on the model involved.
This is the factory vacuum check valve in picture one.
Second is the aquarium bubbler check valve still on the back of my aquarium. When mine went out, I checked prices and just used one of the aquarium parts for 2 bucks. My first one lasted 8 years before it got clogged.
A broken vacuum line or this valve can cause or contribute to the problem.

vacuum check valve 2.jpg (32.64 KiB) Viewed 802 times

bubbler.jpg (65 KiB) Viewed 802 times

[2000gmcsafari]

Thanks for your informative reply. I will try to find a bubbler around here local.

[smokinjoe]

Hey I got the check valve but where on the vacuum line do I put it. The other valve is a 3 way...