1991 Ford Ranger AC Missing

[muwaha]

Hey All,

The previous owner ripped out AC on my 1991 Ford Ranger 3.0 V6.
I know the AC line is missing, but something else is missing and I don't know what the part is called.
Does anyone have a picture of what the AC system is suppose to look like under the hood by chance?

 

[lil_Blue_Ford]

Chances are, it stopped working, and was in the way of some repair and got ripped out. Pretty much have to replace it all at this point most likely because you don’t know where the problem was, how much dirt got in the system, and some of the system should be replaced any time it’s open. I just went through this with my 92. Don’t have any pics at the moment though.

I put a known good pump (came off another truck I have because I’m changing motors in it), new suction line, new liquid line, new condenser, new accumulator, and new orifice tube. Took a gamble that the evaporator was good since everything was there except the pump and suction line. Couldn’t get the liquid line to come off the condenser and the condenser had been open for who knows how long on the pump side so it seemed smarter not to gamble on that. So that’s pretty much what you’re probably looking at. Replace it all, vac it down.

 

[muwaha]

I already replaced the blower and blower resister.
I don't know what I have in the truck still (and replaced) and what parts are missing.
RonD told me in another post that the part missing is the Accumulator.

I attached pictures of my engine to help.
I know it's the AC Line itself, and the other part seems to be a tall cylinder (based on how it sits in the engine).

There's also a cylinder shape thing on top of what I believe to be the evaporator but I don't know what it is or how it plays in.

 

[Bird76Mojo]

The reciever/dryer is missing. Also the orifice tube will need replacing. Plus any hoses that connect to it all.

 

[RonD]

The "cylinder thing" is the Vacuum reservoir, not part of AC system
Yes the Evaporator is under it inside the "heater box"

Receiver/drier/accumulator are all one thing
example here: https://www.picclickimg.com/d/l400/pict/112623325340_/A-C-AC-Accumulator-Drier-Fits-1983.jpg

You need to use R-134a and R-134a compliant parts, the evaporator is fine to use as is the condenser, but either could have leaks which is why the previous owner deleted the system
The 1991 Ranger would have used R-12 which is no longer available

You also need a Condenser, sits in front of radiator, and the compressor
Then the three AC lines to hook it all up

Compressor to Condenser
Condenser to receiver/drier
Evaporator to compressor

You need to use R-134a and R-134a compliant parts, the evaporator is fine to use as is the condenser, but either could have leaks which is why the previous owner deleted the system
The 1991 Ranger would have used R-12 which is no longer available

These are the parts of the newer R-134a Ford AC systems: https://www.ford-trucks.com/forums/attachment.php?attachmentid=497&stc=1

The lower connection on the evaporator usually has the Orifice tube inside it, this is what makes AC work
It releases the High Pressure "freon" slowly into the Evaporator, as "freon" is released it expands and pressure drops, and this is what Cools the evaporator
Pictures here: https://www.therangerstation.com/forums/index.php?threads/where-is-orifice-tube.177316/

Orifice tubes are color coded, Blue is the standard one used in Fords
It has to do with the hole size, the "orifice size", as to how fast or slow the "freon" can pass thru the hole

 

[muwaha]

@RonD I had a mechanic look at my truck (free of charge) and he says the condersner is still on the Radiator..

It would be nice if I had pictures but I'll work with what I got lol.

 

[RonD]

Good stuff

The condenser is on the "high pressure" side of the AC system, so on a warm day, 100degF, it must be able to hold 325psi of pressure, that's ALOT of pressure
Consider your tires, they only need 30psi to hold up 3,000lbs, lol

This is why condensers are the most common leak point, that and they have a lot of tube length to get corroded spots


If your condenser has been exposed to the outside air for a long time it may be bad

Once you have all the parts put together I would have the system Vacuum tested, for sure, so you don't waste money on "freon" if it leaks

 

[19Walt93]

Since the evaporator- and I assume condenser were left open to the air and not capped, I expect there to be corrosion in both. It's worth pulling the orifice tube and flushing both of them before doing anything else. Wit a/c flush solvent.

 

[muwaha]

What's the orifice? I'm sorry, I'm ignorant but trying to learn.
I took pictures of what is in my truck (at the firewall).
There's a black thing that sits on top of the evapator (I think it's called), that circular tube thing but no clue what it goes to.

 

[RonD]

1st pic is the Vacuum reservoir, not used in 1991 by AC
2nd pic ?????
3rd pic top tube of Evaporator, should be one just under it at lower end of heater box, Orifice tube should be in lower one, I think
4th pic ?????
5th pic, broken vacuum line, nothing to do with AC
6th pic ?????


AC works by compressing a liquid, like R-134a, and then letting it UNcompresses in the Evaporator

The Orifice Tube has a small hole(an orifice, lol), on one side of it is the compressed fluid, on the other side any fluid passing thru that small hole can UNcompress which cools down Evaporator

Compressor>>>>>>(high pressure)>>>>>>>>>>>>>Orifice Tube>(low pressure)>Evaporator>>

Orifice tube picture: https://partsavatar.ca/product-images/fixed-orifice-tube-cooling-depot-38621-pa6.jpg

Just slides into an evaporator tube, they come in different colors to denote the size of the "hole"/Orifice, you want to use the Blue "size"

Takes the place of an Expansion Valve which was used on older AC systems

 

[muwaha]

The 4th pic was suppose to be the housing (I think is the term) that the accumulator sits in (if the accumulator is a circular tube device that sits straight up).
I do not know what the 2nd pic is myself I think I uploaded the wrong picture.. same with the 6th pic.

So I shouldn't worry about the vacuum reservoir unit and cabling? Here I've been scrambling my head trying to figure out how it plays into the AC lol

 

[RonD]

No, no vacuum is used for AC in 1991, 1995 and up vacuum is used to operate Cab Vents, i.e. defrost, panel, floor, pre-1995 they are cable operated, sliders on dash
So vacuum was still not used for AC directly

 

[muwaha]

@RonD If I can ask, do you happen to know where the WOT for the AC Compressor is located?
I know that the knob that the AC Control Knob connects to has a purple wire and I've tracked said wire to under the main fuse panel with the 60 Amp Ignition, etc.
I honestly have no idea what this device looks like, but I want to confirm this is where the purple wire goes to.

I am having a hard time finding a replacement knob, so I was thinking of getting away with a simple On/Off switch to trigger the AC to kick on when I get the Accumalator and AC Line re-installed and get the main belt running over the AC Compressor again.

Previous owner ripped the AC Line, Accumalator out, and ran 2 belts to bypass the AC Compressor.

This is the only documentation I could find on the WOT.. I even search the Tech Library here but it seems there is no records of the WOT or I didn't look under the right category (I looked at Heating & Cooling, and Engine). The Wiring Diagrams has the WOT, but obviously it doesn't tell me where it's physically at under the hood.

 

[RonD]

Yes, should be with the Fuel Pump relay and EEC relay under the engine fuse box

Looks like this: https://www.explorerforum.com/forums/attachments/relay-jpg.35945/

Green is FP relay, Brown is EEC relay, Black is WOT relay

Don't see a purple wire in a 1991 on WOT relay

And dash AC on/off doesn't connect to WOT relay in any case, Computer controls WOT relay, and it only turns AC off, not ON

1991 AC
Fuse 7 in cab-----(Yellow wire)-----AC switch----(light green/purple stripe)-----
----pressure switch----(Green/orange)--------WOT relay-----(black/yellow)--------AC Clutch

No purple wire

 

[muwaha]

Ahhhh Thank you!
I have a purple wire that comes off the AC Control Panel Knob in the Cab, and I literally traced the wire all the way to the wiring that runs to some kind of connector before it reaches the AC Compressor. It's literally the only wire off the AC Control Panel Knob that I can't figure out. I know the other wires on the knob control the blower (Low, Med, Med-High, High), since the Control Panel Knob gets pushed in to activate AC, I've been thinking that this is the wire that sends the signal back to the computer to activate the WOT/AC Compressor to kick in.

I found the whole AC Control Assembly for my truck for like $80, I just need the knob not the whole dang unit.