Zeus1987

Okay i decided to try and tackle why my A/C cuts in and out when the truck is not moving. Last night i hooked up the Recovery machine and pulled 1.38 lbs out of it which means it was overcharged. Then I vacuumed the system down to 500 microns and recharged with exactly 1 lb of R134.

Then , i ran the A/C and i could watch the high side pressures climb fairly quick up to ~350 psi and then the compressor would cut out and eventually the compressor would re-engage and the process would repeat.

The whole time the engine fan is just running at a constant speed. The Vistronic fan clutch does not seem to working correctly or something is not telling it to turn on. I tried looking all over for the fan wiring but i can not find it all it must not be routed along the engine block correct?

I do not have any codes except when i pulled fuse #17, then i got a code for the fan and the wastegate solenoid.

I did some searching online last night and heard about the fan eating the connector/wires for the fan clutch.

Where exactly is the connector for the fan clutch ?

What tells the fan to kick into high when the high side pressure gets too high ?

Any help is appreciated

Zeus1987

So today i was able to crawl under the truck and i found the harness for the fan clutch, all the wires look good in the connector and the pins inside look good also. The way the harness is routed tells me that it has never been touched, spliced, or even cut.

I guess the next step is to get out the volt meter and see if i am getting power to the connector, continuity across the fan, etc .

papaduck

More than likely the clutch has failed.

I had my circuits checked at Dodge dealer as I did not have the equipment to check it. Truck was running about 5* hotter than normal at highway speeds and A/C was getting warm at stops. My clutch had gone south.

I replaced it Monday, got the loaner tools at Autozone. The are 2 tools in the set, one fits the 36mm nut and the other fits in the bolt heads on the pully. There is a 1/2 drive hole in the handle of each. I first hit the 36mm wrench with a hammer, would not work, belt would slip. Used both wrenchs with a 1/2 ratchet on one and a breaker bar on the other and the nut came loose very easily. I took precautions to prevent the wires from coming loose in the shroud to keep the wires from being cut by the fan.

I can now hear the fan kick on and off as it is needed and the A/C stays cold at stops.

hyperrcng

From what I have been reading, there is no provision in the computer to kick in the fan when the a/c pressure gets to high. Only thing it will do is kick out the compressor as a safety. That is why some of us are installing pusher or puller electric fans. Also that is one reason we are losing freon when there is no leak. It is getting pushed out due to the high pressures.

Zeus1987

Last night i crawled under the truck again with a multimeter and i had 5 volts and 12 volts at all of the right places. I found the wire for "park lockout solenoid control" and i grounded it out on the frame and all of a sudden the fan came to life ! i ran the A/C and it was 27 degrees coming out of the vents.

I am so close to removing the wiring for my smoke switch and just running a ground wire to turn the fan on when i please. I was also going to stop by the dealer and ask them if the ECM monitors A/C pressures, and what does "park lockout solenoid control" do ? I am getting mixed answers on whether or not the ECM monitors A/C pressure.

Totallyrad

Zeus, on my truck I had a problem with the AC getting warmer over time. I had the dealer check the AC, they said it was low. They recharged it under warranty, added dye and sent me away. About 30 days later I was back with the same complaint. This time they determined the engine fan clutch was bad. They installed a new one, recharged the system and all was well. They're explanation was that when the engine fan doesn't run the high side pressures will cause the the high side relief valve to vent freon. They use this, rather than an AC cut-out switch to save the compressor.

Based on your findings, if you can get the engine fan to engage by grounding a wire, I would suspect you have a bad sensor somewhere and that may not set a code. IMO, a visit to someone with a Starscan tool might get your system back to working properly without having to cut into the harness.

I also found this info, which I think is for an 04.

ECM Side: Fan Clutch:
1) K160 18BR/OR Park Lockout solenoid 1) Green
2) K900 18DB/DG Sensor Ground 2) Black
3) F856 18YL/PK Fan Speed Sensor 3) White
4) Not Used 4) Not used
5) K160 18BR/OR 5 Volt Supply 5) Orange
6) F504 20GY/PK Fused Ig. Sw. Output 6) Red

SpeedyWS6

The ecm does in fact monitor A/C pressure as the ecm controls compressor engagement. It is my opinion that the ecm is just slow to respond to high side pressure swings when it comes to the fan.

I have watched several trucks flirt with the pop off valve especially on hot days with cold engines. Then once the engine gets warm and the fan speed increases to compensate high side pressure falls in check and the a/c magically drops 20 degrees colder.

Zeus1987

A couple of times i could watch the high side pressures get up to around 375 psi and then the clutch would kick out. I checked the relief valve at the back of the compressor and it is pretty dry. Anyone know what it pops off at ?

I am using the schematic attached

I am thinking that the "park lockout solenoid control" wire is looking for a ground and it is up to the ECM to provide that ground. looking at the schematic the transmission solenoid assembly provides the sensor ground. Next thing i am going to do after talking to the dealer is see if i have continuity from the solenoid control wire on the fan clutch connector all the way to connector C2 pin 43 on the ECM.

Spooler

The actual factory charge is 1.88lbs. You were actually low. I run 2.00 lbs in my system but I have a different orifice tube than stock but I think this is the new part for everyone else that has gotten a new orifice line since about 3 years ago. Install a pusher fan on it and be done with it. This is not a new problem, it is actually a programming problem. I will get you two threads to read.

Spooler

Here is one.

https://www.dieseltruckresource.com/...d-t245620.html

Spooler

Here is the orginal when we had a Engineers Ears. This reading should be a manditory...LOL

https://www.dieseltruckresource.com/...ger+side+vents