Fans not blowing fast air

[JohnnyC]

I've noticed recently that my fan is not blowing as hard as it used to. A while back I had some engine work done and my mechanic tightened up a squeak i had on a pulley. It was loud.

How can i make my fan blow faster air. My vent one is not very fast, even the circulating one which used to be the best and blew coldest is not what it used to be. Also my AC is nothing.

Any ideas something i can do? Reasons?

 

[John Robinson]

Check for a vacuum leak. First place to look is at the vacuum control switch.

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One hose coming out of this switch goes to the cruise and one goes to the heater doors. Passenger side under the fuel rail cover.

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Put a piece of hose on the end that goes to the engine and pull suck on it to pull vacuum. If it does not hold vacuum replace with the AC Delco part it is only about $8.00. If this switch is good then check the small vacuum hoses they become brittle with time and in my case they were bad where they connected to a fitting.

 

[JohnnyC]

I pulled out the vacuum check valve and blew it out a little. It works a little better, but i'm still not feelin the fan/blowing as hard as it used to. It was only 75 degrees yesterday and in a 20 min drive it was terrible, so hot in the car and the fan was just not doing it.

How can i check the blower motor and resistor?

 

[John Robinson]

I pulled out the vacuum check valve and blew it out a little. It works a little better, but i'm still not feelin the fan/blowing as hard as it used to. It was only 75 degrees yesterday and in a 20 min drive it was terrible, so hot in the car and the fan was just not doing it.

How can i check the blower motor and resistor?

You do not blow in the check valve you suck on it to pull a vacuum. With the age of your car I would just get a new check valve. Do not get one from an auto parts store unless it is the ACDelco. The cheap ones may only add to your problems. The difference is only a couple of bucks on a $7.00 item. After that check every vacuum hose for cracks at there connectors.

With the air on turn off the auto button and press the button that shows the air in the car being recycled. This should automatically set the fan to hi speed. Also check the vents to make sure they are fully open and pointing in the right direction. Don't laugh I thought my air was not working properly until I readjusted the vents. I had forgotten that my hot blooded wife turns all the vents on her.

 

[Rabbit]

Does your fan speed control work? My was acting up & I cleaned the 2 connections on top of the blower housing to correct the problem.

 

[JohnnyC]

I picked up one of those vacuum check valves from Pep Boys last year sometime because it had a big hole in it. My air was only blowing up out the dash defroster. That fixed that problem. So thats very new. I also didnt hear or feel any leaks along the little hoses.

My fan does work. I can also hear it going. Manual climate control. There is the 4 fan settings. 1 is "on" doesnt really do much, 2 is not much either. Its really only until the 3-4th light that the fan blows much.

I can check the connections later tonight.

I need to get this resolved before it gets ANY hotter here in NJ. Its cooler if i just lower both windows down! I dont think its blowing cold enough. I should also get my AC charged up. Never been good.

 

[BlackIce]

My air was hot and the fan was not putting enough out fast enough. Gave it a recharge and put in a new blower motor and it works great now.

 

[ecss]

Try this.

Turn the ignition On.

Turn the rotary knob to any mode but off.
Such as Max, Norm, Bi level, Vent , Heater or Defrost

Then put blower switch in Lo. Listen for the Blower Motor noise.
Place the blower switch in MI, Blower Motor noise/speed should increase.
Place the blower switch in M2, Blower Motor noise/speed should increase.
Place the blower switch in HI, Blower motor noise/speed should increase.


If all of the above prove correct but the air flow is still weak the Blower Motor is most likely bad.

Another test is to measure the voltage going to the Blower Motor.

If you have a volt meter, unplug the electrical plug under the hood that goes to the blower motor. Place red probe into the connector Purple wire. Place the other probe to ground. At high speed you should measure 12 volts or more at the plug. If that checks out I'd replace the Blower Motor.

Here's the schematic and current flow for the different fan speeds.
In high speed mode the high speed blower motor relay closes and 12 volts is directly applied to the Blower Motor. For the 0ther 3 speeds, the current flow goes through the blower motor resistors.


You can follow the current path for the different blower speeds by following the different colors.

LO speed current path is Green
MI speed current path is Tan
M2 speed current path is Blue
HI speed current path is Pink

 

[JohnnyC]

If you have a volt meter, unplug the electrical plug under the hood that goes to the blower motor. Place red probe into the connector Purple wire. Place the other probe to ground. At high speed you should measure 12 volts or more at the plug. If that checks out I'd replace the Blower Motor.

On high, I got 12.6 V at the plug.

 

[ecss]

With 12.6 volts the motor should be going full speed.

Pull the motor out of the housing, plug the connector back on and turn the fan on and verify the motor runs at high speed.

If the motor is not bad could be the following.

Evaporator core fins clogged with dust/dirt.

Rodents have built a nest inside the blower area.

I believe the air flow from the blower motor goes through the evaporator then the blend door deflects the air through the heater core or around it depending on the temperature you want, then the vacuum operated actuators determine what vents the air comes out of.

 

[John Robinson]

Rodents have built a nest inside the blower area.


I betting on the rodents.

 

[JohnnyC]

I'll check the evaporator core for dirt, etc.

I did notice one thing that seemed odd to me. When i was checking the voltage on the plug on the passenger side, i found that air was blowing up and out infront of the windshield (not inside). There is a vent there. Is that normal.

The blower motor "works", just i dont think its getting cool enough.

 

[ecss]

That's the fresh air intake.

That's probably normal.

I checked mine with the engine not running and did get some air blowing out of that area.

With the engine not running, there is no vacuum to operate the actuators that control the different vents.

 

[JohnnyC]

Not to ask a stupid question, but where is the evaporator core? I checked my Haynes and Chilton repair manual, but didnt mention it. Is it near the radiator?

Is it possible a pulley is looser than it should be?

 

[ecss]

Did you pull the blower motor out of the evaporator housing and verify it spins free?

Here's a pic. of the evaporator housing which is bolted to the passenger side firewall. You can unbolt half of the case to expose the evaporator core.

 

[JohnnyC]

Ok. I cheated a little and just took the blower motor resistor off. Looked down inside and it was clean as a whistle. It was +90 F today and i drove a little, its not cold air AT ALL. I tried the AC, the circluating one, and even the one out dash and feet. All blew just hot air. The air does blow out at a decent rate (not as fast as before or as i'd like)... its just not cold or anything.

Anything else? Charge the AC system?

I'm gonna have to take this to my mechanic soon.

 

[ecss]

Ok. I cheated a little and just took the blower motor resistor off. Looked down inside and it was clean as a whistle.

Anything else? Charge the AC system?

I'm gonna have to take this to my mechanic soon.

:nono When you looked thru the hole for the blower motor resistor assembly, you're looking at the back side of the evaporator core. You need to look at the front side of it.

As for the AC not cooling, does the compressor clutch engage? If it does, is the large metal pipe coming out of the evaporator core cold? How often does the compressor clutch cycle?

 

[JohnnyC]

ecss I knew you were going to say that. :ugh. It was worth a try.

It was well over 90 this weekend and i thought this might be alittle too adventureous for my skill level. I started to unbolt things early sunday morning, but it was just too hot and it looks like a lot infront of the blower motor housing to remove before the housing could be pulled off. I "may" give it a try later on when its much, much cooler outside.

I did find a little hose on the bottom of the blower motor that was not connected to anything. It "appeared" to go to a hole along where the evaporator core would be. So i plugged it back in. It really didnt have much effect. :confused

I DID check the large metal pipe next to the evaporator core. I was reading my Haynes repair manual. It was the same temp as everything. It never, never got cold. Or even cooler. I had it running for 10-15mins with the AC on high. Not sure about the compressor. I'll check that tonight. Things seem to be "running".

Its not just the AC, i dont get cold air from inside circulating one, etc just blows outside temp air. I went to work early today just to avoid the +90 its gonna be today. The drive home is gonna be hot.

 

[ecss]

It appears you have two problems. Low air flow and the compressor not engaging.

For now, I suppose you can live with the low air flow but need to get the AC working.

You only need to split the evaporator case. Shouldn't have to take the driver side of the case off.

I've never tried it but if you just remove the blower motor and shine a light towards the front of the evaporator core you may be able to see if it's clogged.

The hose you found probably was a drain hose.

If the clutch on the compressor doesn't engage when you turn the AC on, you could be low on Freon. Which indicates you have a leak in the system.

At the big metal line going out of the evaporator core there is the pressure cycling switch. It has a half dollar size connector plug with two wires going to it. If you remove the plug and use your ohm meter and measure the resistance across that switch you should read zero ohms. That would indicate there is enough Freon to at least allow the AC compressor clutch to engage.

If that checks out, you can take a piece of wire and short it across the plug end.
Start the engine. When you turn the AC on. The clutch should engage and cold air should come out of the vents.

If you want some phone assistance, PM me your phone number and a time to call. I'm in Baltimore, MD.

 

[JohnnyC]

ok, so i took to my cousin's garage today after work. It was 101 F today. He charged the system up with Freon. He said i was all out. It is much, much cooler now. But the fan still seems a little weak. On high it was just ok i guess. I wish it would blow faster, air/fan speed not temp. The circulating one is blowing faster than the AC. Is that correct?

I did notice the car surging more now. I had the AC on high all the way back home 15-20 mins. Is that normal? System needs to settle down? I'll check back with him tomorrow.

I will be back there friday afternoon (sort of part time/hobby work) and he will check for the leak.

I'll see what i can do about checking the evaporator core of debris.