AC question

[garyp285]

Ok I've been twice to get my ac charged, and both times the pressure goes to 400 and the condenser is as hot as an iron, so we had to abort. I did install a new liquid line with orfice.
The fan is not doing much, and don't how to check it out. I've read where a lot of people have bought an electric fan for the front, relayed to the compressor clutch.
My diesel shop is swamped so it will be a while before I can get it in there.
Thanks for any tips in the meantime.

 

[garyp285]

Update, I took it to a Ram shop where a friend works, and he checked for codes, none, and vac and charged the system, the fan kicked in as soon as the compressor came on and now its doing great. That fan can move some serious air, and he said they very seldom have to replace one except for wires getting sucked in it.
Thanks for all the advice

 

[Motorhead]

Update, I took it to a Ram shop where a friend works, and he checked for codes, none, and vac and charged the system, the fan kicked in as soon as the compressor came on and now its doing great. That fan can move some serious air, and he said they very seldom have to replace one except for wires getting sucked in it.
Thanks for all the advice

So what changed other than a different shop doing the work? I am curious

 

[garyp285]

The only thing I saw is he hooked up the drb3 to check codes, and maybe the fan, but said everything looked good.
Also I noticed the vac and charging was quicker than the last time. I was just happy when I pushed the ac button, after turning to max and fan on high, to hear the roar of the fan.

 

[Tuesdak]

Installed new evap, drier,while doing the blend doors. 03 2500 CC CTD
Went to get it vac and charged, and after adding freon the high side went way over 300, with the compressor running, and the tech said something is wrong, and evac'd it back out.
We did not hear the fan clutch kick in, and he did not jump the low pressure switch. He said the machine adds the freon to the high side, which I know nothing about.
I know we did not leave any plugs in the new parts, but it seems stopped up somewhere, and my searches say over charged, or the orfice, or condenser could be restricted. It did start cooling until shutdown.
Thanks for any advice, seems its one thing after another for me.

IMO your system is acting as designed: You have run into a design defect that appears to affect 2003-2007. In short when the engine is cold and the rare time the cooling fan doesn't have morning sickness: the cooling fan is not commanded on and the compressor is not told to kick off when the high side pressures skyrocket. Generally the overheated condenser condition from no airflow causes the high side relief to dump 1 LB of R134a out of the system around 500 psia. Warm the engine up before turning on the AC and this appears to allow the AC controls to kick out the clutch when needed. Another marginal solution is to strap an electric fan on the condenser.

Below is a long read with a DC engineer getting involved doing everything (like later model years have a larger orface tube) BUT fixing the computer design defect. IMO electronic fan clutches are told not to turn on at all to overcome morning sickness for the first 2 min after startup. (Seen on other rides like Trailblazers with the EV fan clutch where ECT just runs away after startup.) The real Dodge defect is why the ECM sometimes doesn't turn off the AC when the high side gets way too high during the same cold startup.

Morning sickness is when the cooling fan is roaring for a couple min after startup on a cold engine. It was either locked up on shutdown or the working fluid leaked back into the working chamber due to the position of the fan clutch when stopped. You can almost count on a fan clutch to have morning sickness on startup and the rare time it doesn't is when the assumptions fail. It takes ~2 min at 2000 RPM for the fan to disengage after startup. IMO this exact morning sickness situation and someone jumping on the freeway at max RPM is why the fan controls are locked out for 2 min after startup. (The belt may slip if the fan is at 100% lockup and max RPM, power loss to the fan combined with a cold engine already being down on power, whatever the reason really is...)

The second part be the defect in the AC compressor controls that for whatever reason don't kickout the clutch when cold. 2 things combined, random, and now the typical OEM refusal to fix a defect in design.

The TSB flash update is only for CA emission vehicles. http://www.dodgeram.info/tsb/2004/18-003-04.htm

Long read:

https://www.dieseltruckresource.com...years-101/03-ac-not-working-pass-side-106452/

Electric fan, tight fit, gets some results:

https://www.dieseltruckresource.com...passenger-vents-not-cold-drivers-side-245620/

If the EPA wanted a real case to go after FCA it would be for the constant venting of R134a through the relief valve from this design defect. This paints everything behind the relief valve with dye 1-2 times a year on my 2003.

 

[garyp285]

Wow, you just diagnosed my exact situation. The two times the fan failed when charging freon it was not warmed up, and the last time I had driven on the interstate for 45 minutes to get there.
Thats why it worked perfect the last time, it just likes to be at operating temp.

 

[Motorhead]

I have a late late 5.9, 2007 built in the last two weeks of 2006. The fan clutch on mine has always come on even though very low speed right from the first start of the day. It is amazing to me how just one thing such as a fan clutch readily engaging affects how ones A/C will work or not. I fully understand now why your A/C wouldn't work properly.

 

[petersonj]

IMO your system is acting as designed: You have run into a design defect that appears to affect 2003-2007. In short when the engine is cold and the rare time the cooling fan doesn't have morning sickness: the cooling fan is not commanded on and the compressor is not told to kick off when the high side pressures skyrocket.

Thank you for taking the time to post this information and for providing additional resources. I read the "long read" - very informative and worth the read.

I recently purchased a used Snapon refrigerant recovery machine for use on my own vehicles. A few days ago I hooked my sister's 2003 Ram to the machine to recover and weigh the refrigerant. Her vehicle was showing the symptoms of warmer air on passenger side by 20 degrees. The ambient temperature was 55 degrees when I hooked up the gauges.

I wanted to check the AC performance before I began the recovery process. The truck had been shut off for about two hours. When I started the engine with gauges hooked up and AC turned on, the first thing I noticed was that the high pressure side rapidly climbed to 400 psi. I shut the engine off immediately. I restarted the engine and the same thing occurred. I noticed that the engine fan was barely turning.

I recovered the refrigerant (18 oz.) and leak tested the system (passed). I recharged with 32 oz which resolved the difference in vent temperatures. The pressure situation on the high side never occurred again and I now know why.

So, with your help I now have a much better understanding of the AC problems for this era of truck and I can make a better decision about specific repairs knowing what they will or will not fix.

Again, thank you for the relevant information,

- John

 

[FROGPOND]

Gary
Did you also change the office tube when you changed the dryer. My 06 had the same problem and it was the office tube plugged.

 

[garyp285]

Gary
Did you also change the office tube when you changed the dryer. My 06 had the same problem and it was the office tube plugged.

Yes I did the liquid line with orfice tube also.
Just got back from a 1200 mile trip, and it did great, and I couldn't even turn it all the way on cold. Yesterday was around 90 while towing 5th wheel, and when the engine temp got over 210 or so on hills, the fan would come on like a semi truck, and get it back down it about 15 seconds. Between that and my new Cooper AT3's I'm smiling again.