I just acquired my sisters 2003 1500 SLT with 5.? Hemi... they gave it to me because the A/C was acting up over a year or two (intermittent) and they got worn out driving in a hot truck.
I was upstate Florida visiting this week and they mentioned that they were going to trade the ole girl in on something new. When we went for a ride in it to get some lumber, I realized that I'd like this truck and mentioned it was nice. They gave it to me!
They told me that the a/c sometimes works and other times it just shuts off. I can try to switch it off for a few miles and then try again. I rented a uhaul vehicle trailer and towed my Corolla with the V-8 guzzler. It was hot in there BUT when the AC was working, it was almost too cold. out of my 200 mile return tow, I had a/c for about 1/3 of that trip.

I have access to a friends A/C shop with a snapon A/C machine and today I recovered the refrigerant, replaced the accumulator drier and recharged. Lets start with a measured refrigerant charge. I also replace the schrader service valves as a precaution. I found the old accumulator almost full of oil with dye. A few shops had obviously tried to service this.
Surprisingly I recovered about the factory charge of 1.58 lbs (factory spec 1lb 10 oz)

When it came time to run the compressor to finish the charge, it wouldn't engage the clutch. I had previously checked fuses and played musical relays. I got out the scanner, pulled hvac codes, and found a checksum error (2E0300 2E1300 00 01 checksum fault)

I have access to a similar year truck and I could swap parts to test if one of my modules or the HVAC control head is fried.

Now this is where my skill sets and abilities starts to get thin

Can anyone offer some guidance and experience to a half fast technician?

 

Is the AC fan clutch always running or does not it not run at all when idle and AC is activated?

 

No, the clutch is intermittent... if the clutch engages, the A/C works great.
It is some sort of electrical electronic control issue that I am chasing. Perhaps the high pressure switch.

Does anyone have access to a factory service manual or the a/c schematics?

While I am not electrically illiterate when it comes to the electronic control systems, that is where it becomes frustrating in that there are computers making decisions about what happens when and why... it is that 'behind the scenes' unknowns that I have trouble with...


schematic?

 

An electronic copy of the factory service manual should be available, I pulled one down for my 04 a long time ago. Get that manual and it should have some general discussion of how it works and trouble shooting sequence/tests.

That looks like a great truck. Can't beat free!

 

Thanks, I find myself driving spirited as I have not driven a V-8 in many years. I really like having a truck again, if only I were as cool as the truck looks!

The only other issue to date are that the windshield wipers are inop. I wonder if somehow I am going to find that these faults are interconnected. Perhaps in the IPM wiring (a know issue with some Mopar vehicles) is that all the wiring seemingly looms through the fuse box.

My plan today is to remove and inspect that IPM (integrated power module) looking for signs of loose wiring or corroded pins or connectors. I will have a can of contact cleaner handy. AND the climate control head in the dash. One bloke in Australia youtube took a lot of words over the span of 18 plus minutes to finally get to the point where he unplugged the climate control head and reconnected it and MY PROBLEM went away. So I am hoping (or is it hopping) that it is that easy.

My brother also told me about how they did the Tataka driver / passenger killer replacements on recall. I wonder if the ac / wiper faults are somehow related to them operating on the dashboard and just how invasive a repair that was.... Dealership technicians are only people after all and while one might expect them to be the best of the best, there is no telling if they were distracted by life or farcebook while performing their mundane daily chores to put food on the table.

I swear, it seems like people today have three things that are important, A) getting through the week without getting fired, B) collecting the biggest paycheck possible, and C) getting to the beer store at the end of the day.

 

Thanks fj5gtx,
I found the FSM, great suggestion as I loath Haynes and they're talking to me like I am a child.
I spent a few hours studying.

I also got the IPC (illustrated parts catalog) so usually between the two of those I am usually pretty good.

BUT I found that not only the SENSOR (not a switch) on the compressor discharge line but also that there is a temperature probe in the airbox that senses the evaporator temperature and cycles the compressor so it doesn't turn into a block of ice. Genius!
BUT, again, but
... the FSM then refers me to a publication called "use of a DRB III scan tool and the proper Body Diagnostic Procedures manual" and while hardly any shops or backyardigans other than a stealership have access to a DRBIII scanner (you can have a scanner but the updates are unobtanium) that manual has the values for reading / testing these sensors.

Computers and A-I are going plunder humanity...

 

can't see the airbag recall being related to wiper problem...I've done plenty of them. The wiper uses a mux switch...they wear out and resistance changes can screw up the signal voltages. usually switch or wipe motor.

you're on the right track with the ac. Snap on scanner with show the same info as a drb or star scanner.

1. Hook up the scan tool and go into the Engine Control Module (ECM) with the engine running and check the request.

2. If it is there, check the pressure reading from the pressure transducer, it should be within a few lbs. of the high side gauge.

3. If no request, locate the evaporator temperature sensor and check the voltage on the Light Green/Black wire, it should be in the 1-2 volts range.

 

I must have gotten my thoughts confused, I'll go back as see where I thought airbag/wiper... BUT now I know to check the usual suspects, wiper switch or wiper motor.

My thinking is that perhaps in doing whatever to the passenger airbag, that perhaps the evaporator sensor was unplugged and then maybe not fully reinstalled or something along those lines of thinking.
So last night I got in and when I started the truck, I realized that the A/C was working. I took a ten+ mile drive and it sure was pleasant. I love this truck when I am cool driving it.
Perhaps disconnecting reconnecting, wiggling wires over there did something. This morning, nothing. THEN this afternoon I started and no AC but then after a few minutes of idle I could sense the clutch kick in and then the hot air started to cool. I cycled the snow flake (waiting 3 minutes off before back on) and it engaged.

This got me thinking. My brothers 2014 Grand Caravan, when you choose A/c or start the vehicle there is a wait time before the A/C starts to blow... Does the 2004 1500SLT use some of that similar computer logic? Is there a delay between starting the 5.7 Hemi cold and when the compressor engages? (my 2002 Chrysler TnC does not have any delay)

While I don't think I saw in the ECM any air conditioning tiles, I can't say that I looked there. (Autel MaxIM 608? scanner w/key programming) I did find and clear about 14 set codes for various systems.





ECM Selected

BCM Codes [noted and cleared]

HVAC selectedHVAC

HVAC code [HARD CODE, can't clear]

HVAC codes erased

HVAC code remains


** Now, my brother told me that the wipers died straight up and he removed the arms and set them level and RainX the window. I did pull the fuse so that I didn't turn them on by mistake and have them trying to wiper the firewall through the hood

So, I have not done anything to the wipers other than pull the fuse and I happened to note that wiper related code/

Most important things first, fix the A/C!

Thank you for your experience and guidance primem
MUCH APPRECIATED MY FRIEND!

 

In the FSM that I was reading it said or eluded that the evaporator temp sensor was able to be changed without recovering the refrigerant BUT it appears that to change it the airbox need to be on a workbench... Is it possible to R&R the evaporator sensor in the vehicle?

** you mentioned test the
I don't really know what I am looking for or where (other than under the airbox behind the glove box)... how many wires should there be or how many contacts on the sensor plug?
and
Back pin the Lt G/Blk to chassis ground? looking for 1-2 volts with the engine running, a/c selected on?


Again, thank you for your interest.
Cheers

 

Did you check your blower motor? This same complaint I got from previous owner. I just bought it from him. After doing the fuse/relay check/swap, then checked pressure (was in red zone). Yikes! I then jumped the 12v on the relays to bypass them and see if the clutch and fan worked. They did! So before addressing the high pressure issue I checked the blower motor. Not spinning until I tapped it. Swapped it out and cold A/C.