AC issue

skyhighZJ

skyhighZJ

Thanks for your taxes
Joined
May 31, 2012
Location
Aberdeen, NC.
Vehicle: 2011 Ram 3500 6.7 Cummins. Problem: If it is over 95 ish degrees outside and I start my truck the AC won’t start cooling until I start to drive. It is an issue whether I use the key or the auto start. I don’t think it’s RPM related cause I can sit there and rev the truck a bit and makes no difference. It seems to be related to moving. Below 90-95 outside temps it’s not an issue and starts blowing cold within a couple seconds. Any ideas on what to look for. I’m not equipped for AC maintenance and have a decent local shop I “trust” but don’t want to go in without maybe an idea so they aren’t replacing my flux capacitor to engage the Freon bearing coupler or some shit.
 
My truck has done that since it was new and Ford never could find anything wrong. I’ve dealt with it for almost 15 years now but it doesn’t get hot enough up here normally to cause the issue.
 
Morning commute isn’t an issue but doing any mid day driving is miserable for the first few minutes till the ice cubes come out. Louisiana is real proud of their heat and humidity down here lol
 
I'm going to say fan clutch too. My tahoe would not cool at idle. As soon as I started driving it would be cold. Fan clutch fixed it.

Sent from my SM-G955U using Tapatalk
 
shawn said:
Fan clutch? It should be electronically controlled on that truck.
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powerstrokin04 said:
I'm going to say fan clutch too. My tahoe would not cool at idle. As soon as I started driving it would be cold. Fan clutch fixed it.

Sent from my SM-G955U using Tapatalk
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But wouldn’t the fan clutch affect the operating temp of the motor as well? Motor temps are normal all the time. Driving/towing/idling.
 
skyhighZJ said:
But wouldn’t the fan clutch affect the operating temp of the motor as well? Motor temps are normal all the time. Driving/towing/idling.
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Not necessarily. It doesn't make much heat at idle, and at speed there is a lot of air moving over the radiator naturally.

What I don't know about the Dodge is how the ecm control factors into it, if there is a temp sensor that might have failed or is located in the incorrect spot, etc.
 
I wouldn’t have thought much of it, it’s very hot and the condenser just doesn’t have enough air moving across it. If you have it on recirculate, you’re trying to cool the air off inside the truck which could be 120*+ inside, and even if you’re pulling outside air in it’s probably still over 100* due to the surface of the truck.

If I get caught in traffic in my truck it doesn’t cool as good, and my 04 Camry has killer AC, as well as the wife’s van but in temps like these they all don’t start cooling well until you get moving and get some real air over the condenser.
 
shawn said:
Fan clutch? It should be electronically controlled on that truck.
Click to expand...

Would be my guess.

It's probably an ecm lock out of the ac to keep from dumping extra heat into the engine bay. If that's the case I'd like to think there's a company to make a plugin to get around it.
 
I will swing by this next week and have them check the charge. Report to follow. Like I said I haven’t tied anything yet just putting out feelers to get a direction of March.
 
shawn said:
Compressor should be kicking out due to low pressure if that's the case. You'll hear it kicking off at about a 15-30s interval.
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Agreed. Also, a low charge will be masked when there is a lot of condenser airflow present. As soon as the airflow is no beuno, the warm output condition returns
Not empty, just somewhat low
 
So driving in to town this afternoon (ambient air temp 100* heat index of 112*) did the standard stay warm then cool down. Got stuck on main drag behind an accident for a few minutes of no movement. Air stayed perfectly cold even in no movement traffic so it seems to be the initial startup and sitting until the truck starts moving?
 
skyhighZJ said:
So driving in to town this afternoon (ambient air temp 100* heat index of 112*) did the standard stay warm then cool down. Got stuck on main drag behind an accident for a few minutes of no movement. Air stayed perfectly cold even in no movement traffic so it seems to be the initial startup and sitting until the truck starts moving?
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low charge - you were moving, got coolant temp up. Fan locked in on high. Airflow masking low charge. (Just to rephrase what everyone else has said, just differently) that or it is a programming issue across all trucks if similar years have the same issue & have proper charge.
 
a_kelley said:
it is a programming issue across all trucks if similar years have the same issue
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Fan stays off at cold start to help get engine up to temp to reduce emissions.

I don't know this to be true, but it makes sense.
 
shawn said:
Fan stays off at cold start to help get engine up to temp to reduce emissions.

I don't know this to be true, but it makes sense.
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yes if it's electronic control, it Ford (phone typo. But I'll go with it) sure will delay engagement. Even with a true mechanical, cold start engagement is only till the silicone redistributes.

So then the air conditioning continues to work once warmed with low pressures. Initially, it won't be able to cool (move heat to high side) but once the refrigerant expands and gets heat and working it'll continue. Even sub optimum pressure. (Like stated above, just I added more detail as to the physics of it)
 
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