94 Ranger 4.0 A/C Barely blowing

[wesgann]

Hello everyone,
I have a 94 Ranger XTL 4.0L and the AC blows cold/hot but it's barely blowing out. Once you get about 3 inches away from the vents on the dash, you can no longer feel the air blowing - this while the system is on max A/C and high fan. It was like this when I bought the truck a few days ago but I assume this not normal. Could anyone provide any assistance? Thanks!!!

 

[RonD]

Not very clear on your description??

Can you hear the fan(blower) when it is turned on high, so your problem isn't the fan
If so then Google: 1994 ranger blend door
This is a common problem

 

[wesgann]

Hello Ron,
Yes, I can hear the fan on all settings. The blend door is what I thought originally, but I thought when that occurs it either gets stuck in the cold or heat side so you should feel one of them. Regardless of the temperature setting I have it set, I barely get an movement of air. I have half the dash apart and I can see the heater core. I will see if I can find more info on the blend door and locate some better pictures to its location. I'll let you know tomorrow afternoon when I can continue working on it.

Thanks!
Wes

 

[97RangerXLT]

Does the fan change speeds for each setting you put it on? if it does not change speeds, I would look at the resistor for the blower motor. Since you have it apart, I would say that you have checked for blockages.

Are the blend doors working? is more are coming out the defrost vents than the dash vents?

AJ

 

[wesgann]

Hello AJ,
I didn't see any blockages around the heater core, assuming you're referring the common issue of plastic bags and etc. The fan increases with each change of speed. Basically 1 - 3 doesn't allow you to feel anything at all from the vents. I will check the defrost vents tomorrow as well. Is that the best way to confirm the blend door is working? If not, what's the recommended way to check its operation?

Thanks!
Wes

 

[wesgann]

I checked the defrost, same air flow as every other setting - barely any air.

 

[Earl43P]

Here's a suggestion.
Open the hood, and find the Vacuum accumulator for the HVAC.

In early years, it was a torpedo shaped black plastic vacuum reservoir sitting right on top of the heater plenum, near the blower (under the hood).
Later, it became a black plastic sphere, typically located on the passenger side under the air filter box.

It sounds to me as if your HVAC is stuck in the OFF position because it is not receiving vacuum to open the dampers under the dash. It is common for the grey vacuum tubing (to the sphere) to get burnt in half by the exhaust manifold or it cracks due to age.

Closely inspect your vacuum tubing under the hood. The ones you need to find feed from the engine TO the vacuum reservoir and then into the cab at about the center passenger side of the firewall.

A good way to tell if this is your problem is to idle the truck with the HVAC set to Dash Vent (AC off). Turn the key to Off and with the truck silent, turn the selector to floor, defrost, etc. You should hear light thumps as the dampers move. No noises confirms you have a lack of vacuum from the reservoir.

 

[enjr44]

The fan is the squirrel cage type. If it get enough dirt, dust, or other crap on it it will quit putting out air.

Also, check to make sure a real squirrel or whatever hasn't blocked the air intake. If it changes from defrost, floor, vents, etc. I would guess the blend door is working.

 

[wesgann]

Earl,
I moved the selector as you advised. Sometimes it makes a sound like pressurized air being released and sometimes it doesn't. I have uploaded a video to YouTube and here is the link: https://youtu.be/LaLCnzzoAJs

I have also uploaded a link showing how much air is being blown out just so everyone knows what I'm talking about and that link is here: https://youtu.be/34obvvWHW2I

Thanks,
Wes

 

[Harley]

mine was like that until i took the blower motor off and found tons of junk in there...also look around the ac unit fins inside the blower box.

 

[Earl43P]

mine was like that until i took the blower motor off and found tons of junk in there...also look around the ac unit fins inside the blower box.

^ What he said!

I looked at your videos, the vacuum is working when you move the selector, that's good.

Something is either blocking the air intake, which could be seen by removing the blower, or a damper isn't moving. The key damper is the one that moves when you go from the OFF position to any other. Sorry I can't point you to which one that is. What you CAN do is find each of them and run vacuum to each and see if it moves. Frankly, you could suck on a piece of hose connected to the damper and make it move. They move that easily when working properly. I recall one being outboard and forward from the glove compartment, I believe it is for recirculate/fresh air selection. Shouldn't cause your issue.
Another is just up and right of the gas pedal, hard to get to, but you should be able to see it now that your bezel is out. Look left and all the way to the firewall for that one. The blend door should be OK if you get hot/cold.

Pull the blower!

 

[wesgann]

I wanted to give everyone an update. After lots of work and replacing parts that didn't need to be replaced, I found the issue to be the blower motor had been wired backwards. After switching the wires on the plug, air was blowing as it should. However, now it's not cold. Which I expected because I disassembled the motor of the A/C system in this quest. I tried to put a little R134a using those cans that come with a built-in nozzle but I never heard the compressor kick in. At this point, I know I'm past my expertise and I'm going to get some quotes to have the system checked and done by a professional. I know A/C work can be dangerous and for what I'm guessing will be a few hundred job, it seems to make more sense to have it done than to potentially blow up the truck

So I just wanted to give everyone who provided some input a thank you! And hopefully is anyone else is having a similar issue, this post will let them know that it's easy to reverse the wires on the plug and to just start there before taking anything apart!

 

[97RangerXLT]

Thanks for the update Wes. Glad you got it solved

unfortunately, the A/C system might be more than a few hundred to resurrect (especially if a shop does it) depending on what needs to be replaced. Your truck is a 94, and that year they had both R12 and 134a systems in the Ranger. if you were able to hook up a 134a can to fill it, you probably have the 134a system which will make it cheaper for you.

At the bare minimum, you will need to replace the accumulator/dryer, and you probably should go ahead and replace the orifice tube as well (they are only 2 bucks...). and since it is depressurized, that would be a great time to go in and replace ALL of the o-rings.

I completely redid my A/C and replaced everything but the condenser and evaporator. cost me about 600 in parts and misc tools to get the job done. Add another 200 if you replace the condenser and evap, which if your compressor is shot, you will need to do or spend an insane amount of time flushing them out (that was the rout I took, and if I had to do it again, I would probably just shell out the bucks and replace both and say the hell with it).

Here is the write up if you want to understand more about it and see what is involved:
http://www.therangerstation.com/forums/showthread.php?t=144688

AJ