lord_likuid

Hey guys.

4 years a go I bought my XJ and the A/C was not working, I Have attemted to fix it my self but it didnt work. My buddy got an A/C compressor from a junk yard (not sure if it was good or not) but this also didnt solve the problem. I attemted to recharge the unit but this also didnt work. The A/C unit seems to engage but after 2 seconds it disangages..... it attempts to do this mutliple times (just hear cliclking noises)...

would it be a good idea to get a new A/C compressor? do you think it would be somethign else??? it does not blow any cold air at all.

Thanks

jth877

The AC normally cycles every 10 seconds or so for 2-3 seconds, so that's normal. Does it actually engage (clutch spins) or attempts to engage? If that works, I would look at a total system evac (get rid of the old AC oil) and recharge.

lord_likuid

the fan spins for a couple seconds but it does not engage.... Do you think that by changing the compressor it would take care of the problem?

djb383

I beg to differ, cycling every 10 seconds for 2-3 seconds is NOT normal.

An automotive a/c system is somewhat complex and r134a systems are very sensitive to the amount of oil and refrigerant. Might best to have it diagnosed by a pro and see what they say. We replaced everything but the evap and cond last summer, flushed/cleaned everthing, installed new components, measured/added oil then drove to an a/c shop. They pulled a vacuum and added refrigerant to spec for a '98........34F at the center vents....burrrr.

N20jeep

Put some gauges on it.

Could be a restriction on the high side, that would cause the pressure to build quickly and disengage. And is more than likely the cause of your cycling.


A/C work is simple, just have to know what you're looking for.

morettivtx

try recharging the system. it wont engage or stay engaged until there is enough pressure

jth877

The compressor will cycle like that depending on the high and low pressure switches depending on outside temp and system pressure. Later XJs seem to cycle more. LOL, I'll spend a $10 on a can of r134a and get 48 degrees out of my AC rather than spend $400 and get 34 (I believe the spec is in the low 40s)

I agree, go to the AC shop. At least they can tell you if the pressure and charge is correct. Just be prepared to get bent over.

djb383

Glad someone else wrote the FSM. Peace bro. LOL

jth877

Here's the FSM testing proceedure:

Review the Service Warnings and Precautions in
the front of this group before performing this procedure.
The air temperature in the test room and in
the vehicle must be a minimum of 21° C (70° F) for
this test.
(1) Connect a tachometer and a manifold gauge set.
(2) Set the heater-A/C mode control switch **** in
the Recirculation Mode position, the temperature
control **** in the full cool position, and the blower
motor switch **** in the highest speed position.
(3) Start the engine and hold the idle at 1,000 rpm
with the compressor clutch engaged.
(4) The engine should be at operating temperature.
The doors and windows must be open.
(5) Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the engine for five minutes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity. If the
clutch cycles, unplug the low pressure cycling clutch
switch wire harness connector from the switch
located on the accumulator (Fig. 7). Place a jumper
wire across the terminals of the low pressure cycling
clutch switch wire harness connector.
(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor discharge
pressure.
(8) Compare the discharge air temperature to the
Performance Temperature and Pressure chart. If the
discharge air temperature is high, see Refrigerant System
Leaks and Refrigerant System Charge in this
group.
Fig.

Possible Causes Correction
Rapid compressor clutch
cycling (ten or more cycles
per minute).
1. Low refrigerant system
charge.
1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
Equal pressures, but the
compressor clutch does not
engage.
1. No refrigerant in the
refrigerant system.
2. Faulty fuse.
3. Faulty compressor clutch
coil.
4. Faulty compressor clutch
relay.
5. Improperly installed or
faulty low pressure cycling
clutch switch.
6. Faulty high pressure
cut-off switch.
7. Faulty Powertrain Control
Module (PCM).
1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
2. Check the fuses in the Power Distribution
Center and the junction block. Repair the shorted
circuit or component and replace the fuses, if
required.
3. See Compressor Clutch Coil in this group. Test
the compressor clutch coil and replace, if
required.
4. See Compressor Clutch Relay in this group.
Test the compressor clutch relay and relay
circuits. Repair the circuits or replace the relay, if
required.
5. See Low Pressure Cycling Clutch Switch in
this group. Test the low pressure cycling clutch
switch and tighten or replace, if required.
6. See High Pressure Cut-Off Switch in this
group. Test the high pressure cut-off switch and
replace, if required.
7. Refer to the proper Diagnostic Procedures
manual for testing of the PCM. Test the PCM and
replace, if required.

lord_likuid

Thanks guys... I think I may just take it to a shop at least to get it diagnosed.... I hope they dont charge me an arm and a leg.... lol

puredrive

Good luck. I was quoted 865 for a PCM replacement.