A/C Electrical ? 2005 Dodge Neon2.0

BC

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#1
Make
Dodge
Model
Neon
Year
2005
Miles
100K
Engine
2.0
I'm trying to fix this car for a college kid and seemed to be stumped. A/C was working great then stopped at store got back in the car and it stopped working according to the owner.

I checked all the fuses and solenoids including ones under the hood and all are good. I check the low pressure switch and it is closed, and I jumped the switch just to make sure I was not causing the issue. So with car running, ac on, I have no power to the compressor clutch so not sure where to go from here. Electric fans are working and only other thing I could think of would be the switch but fan blows good and I tried ac, max ac, and defrost and still no power to compressor clutch. I hooked gauges up to see what pressures are and there is Freon in the system, not that it would matter due to I jumped the low pressure switch to make sure it wasn't that.

Thanks for any input.
BC
 

billr

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#2
I'm thinking there may also be a high-pressure switch that should be checked.
 

BC

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#3
I haven't had much experience with ac so if this seems like a dumb question... Would the high-pressure switch be on the low side, downstream of the expansion/orifice? Or should I look around the condenser area and before expansion valve? Things sure are tightly packed in this car. lol. Thx
 
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#4
The A/C clutch relay terminals are connected to the vehicle electrical system through a receptacle in the power distribution center (PDC). The inputs and outputs of the A/C clutch relay include:

  • The common feed terminal (30) receives a battery current input from a fuse in the PDC through a fused B(+) circuit at all times.
  • The coil ground terminal (85) receives a ground input from the PCM through the A/C clutch relay control circuit only when the PCM electronically pulls the control circuit to ground.
  • The coil battery terminal (86) receives a battery current input from a fuse in the fuse block module through a fused ignition switch output (run-start) circuit only when the ignition switch is in the On or Start positions.
  • The normally open terminal (87) provides a battery current output to the compressor clutch coil through the A/C clutch relay output circuit only when the A/C compressor clutch relay coil is energized.
  • The normally closed terminal (87A) is not connected to any circuit in this application, but provides a battery current output only when the A/C clutch relay coil is de-energized.
  • Dan Moon says...if you have power at terminal 30, install jumper wire between pins 30 and 87. Clutch should engage ("click").
 

nickb2

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#5
Also, to add to what Dan wrote, when I was working for chrylser back then, a very common problem was the wire harness to clutch was very tight from factory and would cut. Follow the two wire harness from clucth and follow it a foot or so. There were hundreds we fixed cuz of this.

In this snapshot, you see the bracket and two wire harness, it would cut not far from bracket, close to were the connector goes to clutch coil.

Screenshot (223).png
 

BC

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#7
Wow, this some good info! Thanks everyone!!! I jumped the solenoid and compressor kicked on and low pressure side was about 15psi, high side was around 150 so I'm going to add some Freon and check for leaks. When I first hooked the gauges up with ac off I had a reading of 115 on low side so I thought it had enough Freon to kick off but apparently not. And, not mention, I listened to the owner (mistake) and trusted he tried to fill up a/c with freon. I sure appreciate the info guys! You all are awesome!
Thank you.
 
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#8
BC said "I jumped the solenoid".

By "solenoid" do you mean relay, pressure switch, or something else? If you jumped the low pressure switch to get it to work, you will likely need a new switch. 115 psi should be plenty to allow system operation.
If your "solenoid" is a relay, you will need to look for a reason that the PCM is not energizing the relay.
 
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#9
A different diagram - sometimes easier to read.
PS: have you scanned - a code MAY restrict AC operation. ie temp issue.
 

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BC

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#10
No I haven't scanned for a code but I did see the check eng light was on, I'll do that next. I did think the fans should have come on a lot earlier but they never did. Yes, I meant relay switch under the hood in the box is the one I was referring to where I jumped.
Also, I filled the system up, and jumped the solenoid got the pressures close enough, but it doesn't want to come on without the jumper still. Thanks
 
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BC

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#11
Pulled code P0480, I replaced the coolant sensor and now I'll see what happens.

Update... Got power to both rad fan relays. Fan 1 will not come on, but relay is closed so the circuit should be energized. with the engine running, I pull rad fan relay #1 out and fan 2 will automatically come on after a second or two and stays on. I plugged relay 1 back in and checked for voltage at the wire connector where it plugs into the fan with roughly 1.3 to 2 volts. Power is at the relay and they are energized but now power at fan 1 plug. Car still showing P0480.
 
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BC

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#12
After looking at the pdf Kev2 sent, I'm back to thinking the pcm is the issue. Both RAD fan relays are working. Temp switch is new so ect signal should be working. I jumped the low pressure and high pressure switches so the a/c switch sense should be reading closed loop. Only thing left is the pcm issue that I can see. Thanks to everyone for the inputs and thanks Kev2 for the electrical diagram, it came in handy.
Thanks again!
 

kev2

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#13
with the code p0480 I suspect the PCM is restricting AC....
Is code still stored active?
You do know, not all codes will turm on CEL?
this code is often no 12v to relay contrpl side seen at PCM

check circuit fuses. see attachment
 

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BC

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#14
Yes code is still active so I'll recheck it. Thank you Kev2. This sure is a big help.