A/c help please

[Synned]

Okay, well I haven't had a/c since last summer, and since summer is rolling again I kind of need to get this fixed. I thought it was freon, but I put a can in and it didn't get any colder. A few weeks later I bought a can with a gauge on it, hooked it up and it read 100psi. Oops. So the car blows warm air, I don't even know what the next step is to take because I know there is a leak in the line.
What should I do next? I don't really have money to take it to a shop...but will if needed.

Thanks guys
Joe

 

[Fett]

Add freon and dye, wait a few days, use a black light and yellow glasses to find the leak.

 

[04sleeper]

Is the compressor kicking on when you turn on the AC?

 

[Synned]

I don't think the leak is that bad, my gauge showed 100psi of freon, only supposed to be 40.

Should I hear a sound if the compressor turns on? I don't even know what to listen/look for.

 

[Fett]

Yea, your clutch should close...it is pretty obvious if you are looking at it. Start your car and open the hood, have someone turn your AC to max while you are looking at your compressor. If it engages, it will be obvious.

 

[04sleeper]

I don't think the leak is that bad, my gauge showed 100psi of freon, only supposed to be 40.

Should I hear a sound if the compressor turns on? I don't even know what to listen/look for.

Too much pressure will make the compressor not kick on.

You will see the clutch engauge on the front of the compressor when it kicks on and it will start to spin.

Looks like this.

 

[Raginstang]

pretty simple system, like said before, if you feel you have a leak, look around all the lines and connections for dirt buildup. the oil in the system will cause dirt to build op around the leaking area, o-rings are very common A/C leaking points, if you have access to dye you can go that route, but, if you have a fully charged system and your compressor is working and cycling, you probally need a new expansion valve. like stated before, make sure you have the right amount of freon in the system or the clutch will not operate.

 

[jrichker]

I hope that your A/C had the R134a refrigerant in it before you added more refrigerant. If it still had the factory R12, you have made a big mistake mixing R12 & R134. The R134a does not mix with the mineral oil in the R12. The mixed refrigerant will not carry the oil like it should and a compressor failure is likely.

If you had R134a in the system and had 100 PSI, you probably did not have the compressor running. The system probably had a full charge, or close to it. There are several items in the electrical side of the clutch that can prevent it from engaging. Fuse, A/C switch and WOT relay all work together to control the electrical power to the clutch electromagnet.

 

[Synned]

I hope that your A/C had the R134a refrigerant in it before you added more refrigerant. If it still had the factory R12, you have made a big mistake mixing R12 & R134. The R134a does not mix with the mineral oil in the R12. The mixed refrigerant will not carry the oil like it should and a compressor failure is likely.

If you had R134a in the system and had 100 PSI, you probably did not have the compressor running. The system probably had a full charge, or close to it. There are several items in the electrical side of the clutch that can prevent it from engaging. Fuse, A/C switch and WOT relay all work together to control the electrical power to the clutch electromagnet.

I have a 95, and I'm almost positive it was r134a. I even thought I saw a tag on the line that said r134a. Regardless, I got the pressure back down to 45psi, and the compressor still won't kick on. I guess the next thing to check is the fuse, switch and wot relay. Where can I find the switch and the relay?
Thanks
Joe

 

[04sleeper]

I would start by checking the pressure switch on the receiver dryer.

You can unplug it and run a jumper wire to see if it is causing the compressor clutch to not engauge.

This is the first thing I would try.

 

[jrichker]

The compressor off pressures are not a good indication of charge level. With the compressor running and the blower on high with an 85 degreee outside air temp, you will see 28-40 PSI low and 200-275 high with a full charge of refrigerant.

Some review on how it works...
The condenser is up front of the radiator, and it is supposed to condense the high pressure (200-300 PSI) hot gas from the compressor into a hot liquid. The hot liquid goes to the expansion valve located in the tubing next to the firewall. The expansion valve lets the hot liquid expand and become a low pressure (25-40 PSI) cold gas, the cold gas goes to the evaporator inside the car where the fan blows on the evaporator exterior. The heat transfer from the air inside the car to the cold gas inside the evaporator causes the A/C to blow cold air. The now cool gas goes to the compressor where it gets compressed again into a hot gas and the process starts all over again.

For wiring diagrams, see http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp

http://www.autozone.com/images/cds/gif/large/0900823d801ddb58.gif

 

[Synned]

Okay, I just jumped both switches, the one on the freon line i jumped blue yellow to green orange, and the other switch I jumped the two together.
Neither helped anything.
Am I supposed to jump them on the female side or the prong side?

 

[Synned]

Okay heres an update guys.

There is 12 volts at the low pressure switch, there is NOT 12V at the compressor itself. Obviously the compressor won't spin, where should I begin to check for the loss of power?

 

[04sleeper]

Okay heres an update guys.

There is 12 volts at the low pressure switch, there is NOT 12V at the compressor itself. Obviously the compressor won't spin, where should I begin to check for the loss of power?

I would check the wires going to the AC compressor relay.

Not sure where it is located on the SN but on a fox it is located on the inner fenderwell below the MAF next to the air box.

 

[Synned]

So I should just look in the passanger side fenderwell for a relay? Do you know where it comes from?
Thanks

 

[04sleeper]

Maybe this will help.

You can't see it in the picture but it should give you an idea of where to look.

It would be under the filter.

 

[HISSIN50]

The WOT relay on a 5N95 is in the CCRM.

 

[Synned]

The WOT relay on a 5N95 is in the CCRM.

What exactly is the CCRM? The computer?

Does anyone know where the accumulator switch is?

I found someone with almost the exact same problem..

I have a 1994 Mustang and the air conditioning works intermittently. The low-side pressure reads 80PSI. I put some LEDs around the AC electrical and noticed that initially the line out of the AC high pressure cutoff switch is normal (12V) (this feeds into the CCRM). When the CCRM decides to assert the compressor clutch, the AC clutch pressure switch cuts out (goes to 0 volts) and the CCRM disengages the compressor clutch. I do not see a change in pressure on the low side (constant 80 PSI). Also, I never see the clutch engage (compressor never turning).
I have noticed that sometimes, I do get AC.

This seemed to help him out
Try jumping the cycling switch on the accumulator

 

[HISSIN50]

The CCRM (Constant Control Relay Module) is the black box that's located next to your radiator overflow bottle (it has a zillion wires going into it). Really, it is a box with some relays in it (fuel pump relay, WOT relay, etc).

The WOT circuit that Kevin mentioned is a relay that opens the circuit when the puter senses you are at WOT (around 3.7 volts on a fox with the TPS set at about .95 volts - I have no clue if this differs on the 5N95). At WOT, the A/C clutch loses its electrical power so you can have the most horsepower available.
A bad WOT relay or wiring (the different location of the WOT on a fox allows the wiring and relay to get very hot and cause issues) can cause the A/C clutch to not engage when it should, or at all.

Scroll down to the second to last diagram in this link to see what all the pins in the CCRM do (specifically the last pins for you).
If you have a good constant 12 volts going into the WOT relay but not coming out (when you are idling with the AC turned on), I'd look at the WOT relay and its wiring as being the impediment.

Good luck.

 

[Synned]

So on the CCRM, if pin 22 (WOT cutoff) has 12 Volts, but not pin 23 (AC clutch coil control), the wiring should be messed up.
So does the wiring go from the low pressure switch, to the ccrm, to the compressor? WHere does the high pressure switch come into play?

[FROM power] - [High Pressure switch] - [Low Pressure Switch] - [CCRM (WOT relay)] - [Compressor]

Is that diagram correct?

Thanks
Joe