Dodge Cummins Diesel Forum banner
  • Hey everyone! Enter your truck HERE to be a part of December's Cummins of the Month Challenge!
1 - 20 of 26 Posts

·
Registered
Joined
·
217 Posts
Discussion Starter · #1 · (Edited)
I’ve been having an issue with my A/C for the past few summers now. When I’m driving down the road it works just fine. The issue is when I’m parked or idling for any amount of time at all…within 5-10 seconds it will start blowing hot and sounds like the compressor is kicking on and off constantly. Once I start moving again it’ll start cooling back down and working as it should. I had the refrigerant level checked last summer and the guy said it wasn’t very low but it did take a little. He said it could be an airflow issue and recommended I take a water hose and spray the radiator and A/C condenser to see if perhaps they were just too dirty. That hasn’t ever helped. One thing I’ve noticed for the past couple of years is when I initially turn the A/C on after starting her up the compressor make a loud clunk sound and then she starts working just fine…but if I let it just sit and idle for more than 15-20 seconds it starts blowing hot. Any thoughts or suggestions on what the issue may be? I've read that some guys are installing auxiliary electric fans to help with airflow.
 

·
Registered
Joined
·
334 Posts
I’ve been having an issue with my A/C for the past few summers now. When I’m driving down the road it works just fine. The issue is when I’m parked or idling for any amount of time at all…within 5-10 seconds it will start blowing hot and sounds like the compressor is kicking on and off constantly. Once I start moving again it’ll start cooling back down and working as it should. I had the refrigerant level checked last summer and the guy said it wasn’t very low but it did take a little. He said it could be an airflow issue and recommended I take a water hose and spray the radiator and A/C condenser to see if perhaps they were just too dirty. That hasn’t ever helped. One thing I’ve noticed for the past couple of years is when I initially turn the A/C on after starting her up the compressor make a loud clunk sound and then she starts working just fine…but if I let it just sit and idle for more than 15-20 seconds it starts blowing hot. Any thoughts or suggestions on what the issue may be? I've read that some guys are installing auxiliary electric fans to help with airflow.


Clunk is normal on some of our compressors. Verify if your fan clutch is engaging within 10 sec of turning ac on. If it's not there's the problem, if it is check your high and low side pressures.
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #3 ·
Clunk is normal on some of our compressors. Verify if your fan clutch is engaging within 10 sec of turning ac on. If it's not there's the problem, if it is check your high and low side pressures.
Thanks for the tip. If the A/C fan clutch isn't engaging and that's the problem then could I just add a electric auxiliary pusher fan instead of repairing the OEM stuff?
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #4 ·
I tested my theory on why my truck’s a/c isn’t working correctly. I had the a/c running at idle and it wasn’t cooling and the compressor was just cycling on and off constantly…then I put a shop fan in front of the a/c condenser and it started cooling properly and the compressor stopped cycling constantly. I then took the fan off and it stopped working again. That tells me it is in fact an airflow issue and a little electric pusher fan should do the trick. I just don't understand why the setup doesn't work from the factory. What faulty component in the system could be causing this issue?
 

·
Registered
Joined
·
355 Posts
Check the wiring harness that runs between the fan and the radiator, that controls your fan clutch. I went through some water a few weeks ago and my fan cut the wiring harness and my AC was doing the same thing.
 

·
Registered
Joined
·
334 Posts
Check the wiring harness that runs between the fan and the radiator, that controls your fan clutch. I went through some water a few weeks ago and my fan cut the wiring harness and my AC was doing the same thing.
Yep, common issue. A pusher would temporarily fix it, you need to fix the fan clutch.
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #7 ·
Check the wiring harness that runs between the fan and the radiator, that controls your fan clutch. I went through some water a few weeks ago and my fan cut the wiring harness and my AC was doing the same thing.
Could someone post a picture of what the wiring harness is supposed to look like? I'm not sure exactly where to look. I see a harness connector with like 4 or 5 wires that look like they've been cut near the lower drivers side of the radiator but I'm not sure if they're the ones in question.
 

·
Registered
Joined
·
334 Posts
Could someone post a picture of what the wiring harness is supposed to look like? I'm not sure exactly where to look. I see a harness connector with like 4 or 5 wires that look like they've been cut near the lower drivers side of the radiator but I'm not sure if they're the ones in question.
That's them.
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #9 ·
That's them.
OK that's good at least i know what the problem is now. I guess I'll have to replace the fan clutch then because I don't think there's enough wire left to repair the harness. I'm going to call around some local shops to see what they'll charge to do the job. I know it'll be around $215 if I do it myself. I'm just not sure what all is involved.
 

·
Registered
Joined
·
152 Posts
Just need a fan clutch wrench (or air hammer) and i think a ten millimeter socket. Have to pull the fan shroud. Then then the fan. The shroud will colpase enough where you can sneak it out. My truck does the same thing but i just bump up the idle and it solves my problem. Also makes a ton of noise when the engine fan kicks in at 1200rpm sitting still :D

Sent from my XT603
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #11 ·
Just need a fan clutch wrench (or air hammer) and i think a ten millimeter socket. Have to pull the fan shroud. Then then the fan. The shroud will colpase enough where you can sneak it out. My truck does the same thing but i just bump up the idle and it solves my problem. Also makes a ton of noise when the engine fan kicks in at 1200rpm sitting still :D

Sent from my XT603
how do you kick up the idle speed of the fan?
 

·
Registered
Joined
·
152 Posts
Well depends on the year of the truck but with a drb3 (Chrysler's scan tool) you can enable a function that allows you to control your idle with the cruise control. But when i run in somewhere when its 95 degrees out i will bump up the idle which allows the engine fan to speed up. And then usually when i come out the fan is in full lock up and moving a lot of air.

Sent from my XT603
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #13 ·
Well depends on the year of the truck but with a drb3 (Chrysler's scan tool) you can enable a function that allows you to control your idle with the cruise control. But when i run in somewhere when its 95 degrees out i will bump up the idle which allows the engine fan to speed up. And then usually when i come out the fan is in full lock up and moving a lot of air.

Sent from my XT603
Oh you mean you bump up the engine idle speed. i thought you were saying you can adjust the fan speed somehow.
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #14 ·
I called around to some local shops to get some prices on replacing the fan clutch. Most of them were $550-$650 for parts and labor. My friend’s dad is a a/c mechanic at a local shop and he said the aftermarket fan clutches aren’t very good so it’s worth it to spend a little more for the genuine Mopar one. The local dealerships want $450 for the Mopar part but I found them for $297 delivered online so that’s only $66 more than the aftermarket one from OReilly’s. Then I can either install it myself or pay my friend’s dad $75 for his shop to do it.
 

·
Registered
Joined
·
355 Posts
Is there anything left of the wiring harness? If you have 2" of wiring coming out of the fan and 2" of wire coming out of the plug you can solder it back together. That’s how I fixed mine I had to add about 4" of wire because it was cut so bad. I was also able to fix mine while it was still on the truck, the shroud collapse down and you can slide it out of the way, then I unbolted the fan to move it back out of the way so I had more room to get in there and work. Or you can go get a 36mm fan clutch wrench and remove the fan clutch and fix it on the work bench, but make sure you secure the wiring harness back after its repaired or you will be doing this all over again.
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #16 ·
Is there anything left of the wiring harness? If you have 2" of wiring coming out of the fan and 2" of wire coming out of the plug you can solder it back together. That’s how I fixed mine I had to add about 4" of wire because it was cut so bad. I was also able to fix mine while it was still on the truck, the shroud collapse down and you can slide it out of the way, then I unbolted the fan to move it back out of the way so I had more room to get in there and work. Or you can go get a 36mm fan clutch wrench and remove the fan clutch and fix it on the work bench, but make sure you secure the wiring harness back after its repaired or you will be doing this all over again.
This is exactly what I was thinking of doing. I was looking at the harness last night and I have probably 3-4" of wire at the fan clutch and 2" at the plug on the lower passenger side of the radiator. I'm not sure how the harness needs to be ran as I never looked at it before this happened. I’d much rather repair the harness than spend $300 on a new fan clutch.
 

·
Registered
Joined
·
355 Posts
There should be a metal bracket that is shaped like an L that holds the wiring harness, it is held in place by a bolt near the plug and it runs between the fan and the shroud, is that still there?
 

·
Registered
Joined
·
217 Posts
Discussion Starter · #18 ·
There should be a metal bracket that is shaped like an L that holds the wiring harness, it is held in place by a bolt near the plug and it runs between the fan and the shroud, is that still there?
I'm not sure I'll have to check it out. I looked at my friend's 05 4x4 CTD and his looked completely different than mine does. His fan shroud is much different and so is the way the fan clutch wiring harness runs. Can anyone post a pic of the way the harness runs on the early 04 models? Not sure if 2wd or 4wd makes a difference or not.
 

·
Registered
Joined
·
152 Posts
I'm not sure I'll have to check it out. I looked at my friend's 05 4x4 CTD and his looked completely different than mine does. His fan shroud is much different and so is the way the fan clutch wiring harness runs. Can anyone post a pic of the way the harness runs on the early 04 models? Not sure if 2wd or 4wd makes a difference or not.
Is your fan metal or plastic?

Sent from my XT603
 
1 - 20 of 26 Posts
Top