AC not cold during idle but cold all other times

[jerbo1978]

That all will probably help a decent amount.

The clutch fan is a viscous clutch, so it slips (after the initial start), then will engage fairly hard to a 1:1 drive (similar to cold start) when the temp on the fan gets around 220+ something - depending on year, etc. You may hear and feel it sometimes when you pull out after sitting at a long light on a really hot day. Other time is when you restart on a really hot day after just shutting the engine off for a minute or so.

Since your coolant is at that temp at a light on a hot day, it's not the clutch fan and it sounds like it's working ok.
Could be a slower efan if you don't hear it.
Or, could be a bit of a charge issue - which is easily corrected by draining, pulling a vac on the system and recharge with the correct charge - costs some $$ though. You could try adding a little bit by yourself pretty cheaply and easily though.

I missed it if you ever said that you can hear the efan or not.

E fan is definitely not coming on.
Every time I turn AC on or the defrost,I get a check engine light fault code p0481.
Which is malfunction in Cooling Fan control circuit II

 

[pacofortacos]

That's definitely a problem.

 

[jerbo1978]

That's definitely a problem.

Thanks for trying to help me figure this out.
I appreciate it

 

[pacofortacos]

Thanks for trying to help me figure this out.
I appreciate it

You might have a bad high pressure switch causing that code.

 

[04fxdwgi]

Not having the fan running certainly contributes to a high head condition, sitting still.

 

[PaleFlyer]

That all will probably help a decent amount.

The clutch fan is a viscous clutch, so it slips (after the initial start), then will engage fairly hard to a 1:1 drive (similar to cold start) when the temp on the fan gets around 220+ something - depending on year, etc. You may hear and feel it sometimes when you pull out after sitting at a long light on a really hot day. Other time is when you restart on a really hot day after just shutting the engine off for a minute or so.

Since your coolant is at that temp at a light on a hot day, it's not the clutch fan and it sounds like it's working ok.
Could be a slower efan if you don't hear it.
Or, could be a bit of a charge issue - which is easily corrected by draining, pulling a vac on the system and recharge with the correct charge - costs some $$ though. You could try adding a little bit by yourself pretty cheaply and easily though.

I missed it if you ever said that you can hear the efan or not.

I looked, with a flash light, and the E fan is running. I was thinking about having someone charge/balance/whatever the system.

I looked at doing it myself, and it's basically over $100 just to get the can of stuff, and the adapter.

 

[pacofortacos]

I looked, with a flash light, and the E fan is running. I was thinking about having someone charge/balance/whatever the system.

I looked at doing it myself, and it's basically over $100 just to get the can of stuff, and the adapter.

Can you hear the efan though? If you can't it may not be spinning as fast as it should. I can hear mine from several feet away.

 

[PaleFlyer]

Can you hear the efan though? If you can't it may not be spinning as fast as it should. I can hear mine from several feet away.

I don't think so, but I haven't tested it. My HVAC in the truck has basically been in Auto since the day I bought it, other than occasionally when passengers complain about the blower, so the normal engine noise to me includes the fan(s).

 

[jerbo1978]

You might have a bad high pressure switch causing that code.

I was told that the Ram condenser fan is controlled by the PCM....It sends a signal to the fan relay which is attached to the horn mount....which switches the fan on and off.
Do you thinkI a bad high pressure switch would influence the PCM ?

 

[PaleFlyer]

Can you hear the efan though? If you can't it may not be spinning as fast as it should. I can hear mine from several feet away.

I heard it ramp down when I walked out to the truck after work Wednesday, so I think the fan IS working right. I've been remote starting before I walk down the stairs to the parking lot the last week or so, as it's just so darn hot here, it gives the truck a minute or 2 to "blow out" some of the heat before I get in. I put up the driver side sun shade, so rolling down the windows doesn't do much for me right now.

 

[pacofortacos]

I was told that the Ram condenser fan is controlled by the PCM....It sends a signal to the fan relay which is attached to the horn mount....which switches the fan on and off.
Do you thinkI a bad high pressure switch would influence the PCM ?

Yes it is controller by the PCM and yes a bad high pressure (or low pressure) switch will influence the PCM - that's how the PCM knows to turn it on.

 

[pacofortacos]

I heard it ramp down when I walked out to the truck after work Wednesday, so I think the fan IS working right. I've been remote starting before I walk down the stairs to the parking lot the last week or so, as it's just so darn hot here, it gives the truck a minute or 2 to "blow out" some of the heat before I get in. I put up the driver side sun shade, so rolling down the windows doesn't do much for me right now.

It could be that it's just that hot, humidity plays a role too, so if hot and dry it is possible that the system is just maxxed out.

 

[PaleFlyer]

It could be that it's just that hot, humidity plays a role too, so if hot and dry it is possible that the system is just maxxed out.

The thing with that is, it's only when I'm at a light/stopped/crawling along. 40+ and it's blowing COLD air. Slow, and it's blowing cool air.

It seems to me like the fan issue we originally thought, or a compressor/charge issue, as to my knowledge, I think the compressor runs off the belt off the engine right? So low speeds would keep the engine at too low an RPM to properly compress the refrigerant, or the fans just don't move enough air.

I'm also thinking about knocking out the "plugs" on the sport hood, and letting them vent the engine bay at this point, let convection do it's job to help.

 

[pacofortacos]

The thing with that is, it's only when I'm at a light/stopped/crawling along. 40+ and it's blowing COLD air. Slow, and it's blowing cool air.

It seems to me like the fan issue we originally thought, or a compressor/charge issue, as to my knowledge, I think the compressor runs off the belt off the engine right? So low speeds would keep the engine at too low an RPM to properly compress the refrigerant, or the fans just don't move enough air.

I'm also thinking about knocking out the "plugs" on the sport hood, and letting them vent the engine bay at this point, let convection do it's job to help.

You're right on the air flow helping. The compressor does run off of a belt, but usually a charge issue will show up all of the time - unless you are just slightly under.

I just had my truck in Florida and idle AC is maybe about half of moving AC - maybe, hard to tell since the solar effect is so prominent. Sun behind the clouds or temp drop from mid+ nineties to eighties had a huge effect of AC output.

DOES using the recirculation button help at all??

 

[PaleFlyer]

You're right on the air flow helping. The compressor does run off of a belt, but usually a charge issue will show up all of the time - unless you are just slightly under.

I just had my truck in Florida and idle AC is maybe about half of moving AC - maybe, hard to tell since the solar effect is so prominent. Sun behind the clouds or temp drop from mid+ nineties to eighties had a huge effect of AC output.

DOES using the recirculation button help at all??

I haven't thought about the recirc button as a troubleshooting step, but yesterday I was driving around a bit, mid/high 80's, and I idle'd in the parking lot of Lowes about 30 minutes away from home (they were the closest with a specific door I needed), and it seemed like the AC was working okay.

Buddy had suggested I check my engine filter, which I admit I have forgotten about, and I knocked a decent amount of dust out of it by just wacking it on the driveway a couple times. I'm gonna get a new one on the way next week. Fuel econ has dropped about 1.5 mpg, which is like 8%, so...

 

[jerbo1978]

I haven't thought about the recirc button as a troubleshooting step, but yesterday I was driving around a bit, mid/high 80's, and I idle'd in the parking lot of Lowes about 30 minutes away from home (they were the closest with a specific door I needed), and it seemed like the AC was working okay.

Buddy had suggested I check my engine filter, which I admit I have forgotten about, and I knocked a decent amount of dust out of it by just wacking it on the driveway a couple times. I'm gonna get a new one on the way next week. Fuel econ has dropped about 1.5 mpg, which is like 8%, so...

I think the AC being warmer at a slow speed or stopped is normal.
Engine Rpm's are way lower so the condenser belt isn't spinning as fast so the coolant isn't circulating as fast either...

 

[PaleFlyer]

I think the AC being warmer at a slow speed or stopped is normal.
Engine Rpm's are way lower so the condenser belt isn't spinning as fast so the coolant isn't circulating as fast either...

I actually did some testing yesterday, where it was pushing 100°f, and the index was probably getting closer to 110 then I would like to be out in, but when I turned OFF the automatic control, and turned on recirc, I had to slow the fan down, so I think the Auto control is buggy, or needs to understand that the outside temp means the recirc should engage over ~90F once the initial "purge" is complete to drop the interior temp below 150F (or w/e the truck gets to in the sun.)