MoparNJeep

My while AC system has been replaced. Pump, dryer, refrigerant, etc

It was working one day then quit.

Has pressure and no leaks. If I jump the plug on the AC clutch the clutch will kick on.
There is no power to the plug in harness for the clutch but power at the fuse for the clutch.
All fuses and relays are new and good. I tried another relay that was good off my other jeep. The switch on the dash has power as well

The only other part of the system that is not currently working is the auxiliary fan.
I've chased the wires under the hood and dash and wiring is all in great shape.

It's obviously not working because I'm not getting power from the fuse to the plug for the AC clutch but it all looks good.

I know the wiring could have a break and not be visible but I'm kinda wondering if the auxiliary fan not working could be preventing the AC clutch from Turing on.

But the only thing with that is the AC stopped working awhile ago and the auxiliary fan just stopped working recently so idk

Any ideas?

CCKen

Try jumping the Low Pressure Cycling Switch connector on top of the AC Accumulator. The switch cycles the clutch and fan based upon pressure in the system. The switch contacts are normally open and when the switch senses pressure in the system the contacts will close. The High Pressure Cutoff Switch (by the compressor) is wired in series with the Low Pressure switch. The contacts in this switch are normally closed and open when the system pressure is too high. Both switches must be functional for the AC system to operate.


Remove the connector from the Low Pressure switch and jump the two pin cavities using a small paper clip (see pic). Select AC on the Mode Selector. Start the engine. The clutch should engage and the fan should run.


If not, leave the jumper in the Low Pressure switch and remove the connector from the High Pressure switch and jump it. See if it works.


Get back with results.


Low Pressure Cycling Switch connector jumped:





Location of the High Pressure Cutoff Switch:

MoparNJeep

As soon as I get home from work I'll try that.

That is the other thing when I checked for pressure it maxed out the 80psi guage. When unfilled the system it wasn't that high. It was right in the range it should be...

MoparNJeep

So what I understand is if I jump that and it works that switch is bad?

Thanks for the response. MoPar rules

CCKen

You should have your handy dandy service bottle with pressure gauge hooked up when you do this. If the compressor starts check the pressure (low side only in this case).

If the pressure is low the switch may not be bad, if the pressure is within spec the switch may be bad.

Don't forget the high pressure switch.

Go by this chart. You'll be going by the Evaporator Inlet Pressure.

MoparNJeep

Well I jumped the switch and the pressure was right around 50psi.

I put a test light on the ground of battery then in the plug of the low pressure side and ac clutch would turn on. Then I put the test light on the positive side of the batterery then touch the low pressure switch on the other wire and test light would light up.

I repeated this and clutch would turn on except when I touched the second wire on the high pressure side the test light would not light up.

That makes me think maybe the high pressure switch is bad but idk where to go from here.

Don't really want to start throwing money at pressure switches if that's not it. Would changing those empty the refrigerant ?

Thanks for your help

CCKen

If you are saying that you jumped the low pressure switch and you got around 50 psi, are you saying the AC system started working?


If you got 50 psi on the low side that's too high, unless it was around 100*F outside (see pressure chart).


I can't figure out what you are trying to explain in the rest of your post.


When all the AC system components were changed did you take it to an automotive AC shop and have it serviced?

MoparNJeep

Yes when I jumped the low pressure plug and the ac system worked except the auxiliary fan. I then jumped the high pressure plug and ac worked as well

No I rented a gauge set and did it with my dad who is a master mechanic with many years of experience as mechanic for Chevy dealership. He has done this many times. He has not been able to come help me problem solve though.

I appreciate your help, my research has turned up your name on a few different forums. Any ideas on my next step. I don't know that I would trust the gauge from a ac refill can over the proper gauges we used when we first fixed my ac but if it's possible that I have to much pressure now maybe that could be from one of the faulty pressure switches? I'm willing to replace them as they are less than $20 each but I would prefer to learn how to diagnose the problem based off of symptoms. I love problem solving and learning. Thanks again

CCKen

If you jumped the low pressure switch and the system worked there shouldn't be a problem with the high pressure switch. It opens when the pressure in the system is too high (450 to 490 psi)


It looks like the low pressure side is too high with 50 psi.


What all components in the system did you replace? You just say "etc.". Did you replace the liquid line (fixed orifice)? Did you flush the evaporator and the condenser?


How much oil did you add to the system when you changed all those components?


Was the system evacuated before charging?


You may want to take the Jeep to an automotive AC shop and recover the refrigerant and go through the recharge process again.


~~~~~~~~~~~


As far as the radiator fan not working, remove the electrical connector from the engine coolant temp sensor on the thermostat housing, then start the engine. See if the fan runs. If not, the fan may be bad, the power fuse in the PDC might be blown or the relay control coil fuse in the JB may be blown, the relay itself may be bad, or the wiring from the PCM to the relay may be open.


Doing this will put the CEL on, with a P0118 DTC set (ECT Volts too high). After reconnecting the ECT connector, just remove the battery negative post connector for around five minutes to clear the code, or clear it with a code reader.

MoparNJeep

The system was flushed and I believe it was a ounce of oil we added.

When we filled the ac it was in range psi wise where it should be. I'm not sure that I trust how accurate the recharge can is over the gauges I rented where. Though it was really hot that day around 90° out side and probably hotter under the hood so idk

The ac worked great all last summer and this summer when I tried to use ac it would not engage the ac compressor clutch.

The fan works as I have it wired to a switch so I can turn it on manually but it would not turn on when I jumped the ac low pressure plug . All fuses I checked already. I haven't checked the relay for the auxiliary fan yet though

CCKen

The system takes around 8 ounces of oil.


The fan may not run because of the bypass switch [?]

MoparNJeep

I didnt replace the orifice tube.the reciver dryer was replaced. The system was flushed and pressure checked before filling as well.

I'm just not sure why it worked great still has pressure but is now not working. It worked great if I recall it was 38° blowing out of vents measured with a laser thermometer

MoparNJeep

I'll ask my dad on what we put I'm for oil. It was whatever was spec out in fsm. I just don't recall off the top my head.

MoparNJeep

The fan was bypassed before the ac stopped working . I tried disconnecting the bypass to see anyways but no change

MoparNJeep

Okay we did do 8 ounces I had the container in the garage and it's empty