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Need Advice to Replace AirConditioning Compressor in Excursion

4K views 31 replies 18 participants last post by  taledarkside 
#1 ·
So, the frackin thing broke on the way to Heartland.

Patient:
Overworked/Underpaid massive trailer hauling, country crossing, 2000 Ford Excursion V-10 with Auxiliary Air Conditioning (Rear Air)

Symptoms:
Nice little rattle noise when truck is running.
AC no workie
AC blow hot air
Wife not happy
Windows down make noise
Windows down in rain make passengers all wet

Determination:
Fix because wife says so.


Diagnosis (unverified):
Bad AC Compressor

Prescription:
Remove/replace AC Compressor
Recharge System with Freon (55-60oz. capacity)


Request:
How the heck do I do this????
Need it fixed by tomorrow night, so that we can go to Putnam on Friday in glorious palatial and cool comfort.

Worry: High pressure hoses... how do I remove the pressure so that I can remove the unit and replace.

I went to Elgin Super, bought the replacement unit. I went to CarQuest bought the hose and the 60oz. of Freon.

What's next?
 
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#5 ·
Yup, you will need a vacume pump to suck the system down after you open it up. your also gonna want some nitrogen to blow the system out first, get with Ryan, he can bang it out for ya. screen name Ryan, oh and our beloved moparboyy may be able to help ya also.

or just go trade that big boy in on a nice diesel 2500 suburban.
 
#7 · (Edited)
How can we determine that? The clutch does not engage when the AC is turned on and the engine is running.

On the Dakota, there is a low pressure sensor thats get shorted out so the compressor continually runs. Who knows excursions.

I already had left Mopar a VM. Just waiting a call back.
 
#9 ·
Sure you are just not out of refrigerant, and being low makes the compressor not engage?

My venture had a problem that someone said I needed a whole new compressor. Turns out I had a leak in the line (known technical service bulletin) and 2 cans of the refrig w/ the leak-seal worked like a champ last year. After this past winter, voilla, still good :)
 
#10 ·
THe coolant is also the lubricant for the compressor.

Most systems have a pressure - check switch that prevents the compressor
from running if the coolant ( lubricant ) is all gone.


Could just be flat ( leaked ).... I believe you can check the system pressure on one of the schrader valves near the compressor ( have a book ?) not sure what the value should be.


Tom
 
#13 ·
So, update, all great info coming, thanks guys.

We pulled the clutch face off and the outer ring was loose and making a ton of rattling when running. Put the new outer face on, and started it up. No noise.

That part is solved, however, no cool air either.

Just got off phone with Mopar again and he suggested same thing with the 12V check. Only prob is that Greg's voltmeter is at home. Gonna call Glenn (Insomniac) he lives a block away or two and has one....
 
#15 ·
Is your clutch engaging? If it isn't engaging then check if there is 12V at the wire for the clutch solenoid(GY/WH).

If there is 12V
If the clutch is receiving 12V, it should engage. I would check the resistance on the clutch coil, the coil might have burned out. If the coil is burned out, the clutch won't work.

If there isn't 12V
The clutch receives power from the Compressor clutch relay, so the first thing I would check is to see if this relay is working properly. Check for 12V at the coil side, if there isn't 12V then one of the A/C controls is stopping the clutch from engaging. From the schematic I am looking at, it seems that the PCM grounds the coil side of the relay. The coil side of the relay gets power from the fuel pump relay. The PCM receives a signal from A/C clutch cycling pressure switch, Refrigerant contamination switch, and function selector switch. I haven't read all the stuff on this system, but here is how I think it works. Power goes to the selector switch, if you select A/C or whatever, power flows to the rest of the circuit. The circuit has two more switches, the pressure switch and contamination switch. If both of these switches are closed, the PCM receives a 12V signal. This tells the PCM that the A/C system is OK to turn on. Then then grounds the coil side of the relay, which in turn closes the switch side of the relay. This causes power to flow to A/C compressor clutch and the compressor should engage. There is also a diode in the compressor clutch circuit, it is suppose to absorb voltage spikes.

If you want schematics so you can check them out for yourself, I can probably get them for you.
 
#16 ·
Clutch not engaging. Getting a way to test the 12v in another hour.

Thanks!
 
#19 ·
Nah, no meter. Gonna worry about it after the weekend. Got the outer portion of the clutch replaced at least the rattling noise is gone. Will worry about fixing it on Monday and thereafter, I have until Iowa (2 wks) to get it fixed that way.

Thanks for the help.
 
#21 ·
wink ive done a decent amount of work to my ac om my car, including replacing the condenser coil, if its empty of refrigerant you dont need the expensive reclaimer just the evacation pump, which i have. ive got the gages to check the pressures as well.

keep us informed
 
#22 ·
You can rent pressure gauges and the vacuum pump from AutoZone for free. Its going to be hard to check the pressure in your A/C system as the compressor doesn't turn at this point. Do you have reason to believe there may be a leak? The compressor will not turn if you are low on refrigerant. One of the functions of the pressure switch is to only allow the compressor to run if the refrigerant level is correct. If there is no leak the refrigerant levels are correct, the problem is probably in the electric circuit that controls the clutch. If there is a leak, the pressure switch will probably stay open.
 
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