I've got a 2002 Dodge Ram 1500 5.9L. I was having trouble with the truck dying at low rpms and I was getting codes P0320 "Ignition/Distributor Engine Speed Input Circuit Malfunction" and C0000"Vehicle Speed Information Circuit Malfunction". I cleaned out the throttle body and IAC valve. It runs sooo much better. I don't have any check engine light on. However, I still have C0000 code and I don't know where to begin on solving that one. Also, after cleaning the throttle body and IAC valve my a/c started putting out cold air again. I'd just figured it needed to be recharged. The funny thing bout the a/c is that it only blows out cold air when I'm driving. When I'm parked it blows hot. Any ideas on that anyone? Any input or advice is appreciated.

I did some looking around on the net and found that the code I got "C 00 00" from the ignition turn just means all codes have been displayed. No more codes, good for me. I was looking at my a/c compressor with the truck running and a/c on, and the inside pulley starts and stops. Its as if the inside pulley is seizing up. I'm not really sure if this is normal. I'm guessing I need a new compressor?

 

If your AC compressor is kicking on and off every 5 to 10 seconds it could indicate a low charge on the refrigerant.
Oh, more than likely since you said it's cold when you drive but warm when the truck is still, it's probably the condenser fan motor. Pop your hood while the AC is on and check to see if the condenser fan is blowing hard. If the fan isn't working then you can order just the replacement motor, or the whole fan motor shroud assembly. If you shop around online the entire shroud assembly might be cheaper (I found that out after I ordered just the motor) Check out 1aauto for parts, and also they have a ton of how to videos on their website and on you tube.

BTW Welcome to the forum Let us know if you if you have any more questions. If it is the fan motor, I just did mine the other month and will be able to offer some tips if you need.

 

Thanks for the welcome. I don't know too much bout vehicles so please bare with me. I checked the smaller fan next to the larger radiator fan. I didn't see any other fan so I'm assuming that was the condenser fan. I had the truck idling for about 5 minutes with the a/c on full blast and the fan didn't come on once.

If I replace the fan assembly myself, would any of the a/c hoses, or anything pressurized, have to be taken off? I'd rather not mess with the a/c system due to my truck noobness.

Btw, my compressor kicks on and off bout every 3-5 seconds. Does that mean I'm likely just low on coolant, and the compressor isn't going out on me?

 

Yup, the smaller fan on the drivers side is your condenser fan. It should always turn whenever the AC is on. If you have a test light, or even better, a multimeter / volt meter you can carefully disconnect the plug at the back of the fan to make sure that you at least have power going to the fan. (It will be brittle, so be gentle. The red clip slides away, then the plug can be wiggled loose, I have a tendency to break mine). If there is power at the plug then you know it is the fan motor that's bad. If there is no power at the plug then it could be a fuse or relay or a bunch of stuff.
The fan motor can be replaced without having to discharge the AC lines. It is a big pain in the --- to do, took me about 2-3 hours trying to get everything moved out of the way and wiggled around everything else but it can be done. It's about a $80 part and a lot of your own time, or my shop here quoted me over $400 to discharge AC, replace the entire cooling coil and fan shroud assembly, and re-charge the system. Another possible option, ask an AC shop how much they will charge to evacuate and seal your AC system one day, (it will be easier to replace the fan then) and re-charge it on another trip.

* A word to the wise, because your fan is not working the refrigerant is getting hot when your truck is still, this causes your compressor to overheat and switch off, after a few seconds the compressor comes back on and the cycle continues. So, to prevent further damage do not use your AC or defroster when you're driving under 20mph. When you're driving the natural air flow is enough to cool the coil and refrigerant and compressor for normal operation.

 

The compressor cycles like that because of the high pressure switch in the high side line. It is a safety feature to keep from blowing the lines apart and or damaging the compressor.