I just got my 2005 300 3.5L a few days ago and am trying to sort out why my AC won't work. first the wire was cut from rubbing on the belt, so I went to the wreckers, cut off a really nice looking one, and soldered it back on to my harness. It was fully heat shrinked taped and loomed.
I applied power to the clutch directly and it does engage, and the AC gets cold.
I've checked every fuse up front, and swapped the AC relay with the horn relay, and that checks out as working.

I haven't checked the rear fuses yet because I don't have a puller and it's a bit harder to pull those ones out at that angle.

Problem is, there is no power going to the plug at the compressor when the AC is turned on. I checked it with a meter and get nothing.


So where else do I need to check to figure out why my AC isn't getting power at the compressor?

 

Alright, this is getting really frustrating at this point.

Checked fuses and relays - All good.
Checked AC system pressure - All good, low side is 45PSI high side is 225 PSI.
Performed tests on the transducer. There is 5V signal between pin 2 and ground (Pin 1 or vehicle ground). However I'm unable to get a resistance reading between pin 3 (5V supply) and pin 2 or 1.
I've jumped Pin 2 and 3 which should send 5V to the computer like the transducer would (I think) but the compressor still wouldn't come on.
If I manually power the compressor directly from the battery it runs fine, pressures stay where they should be and the air is nice and cold, right around 16*C with the cabin and outside still warm.

So I'm really confused here on what I should check next or what the damn problem is.

 

get a wire diagram if you ca jump the ac rela and the compressor work hen the output side of things are good look at the ac clutch control side what will not make it turn on that way aka the transducer or pcm o bcm or control switch

 

This has the wiring diagrams
http://oskin.ru/pub/chrysler-dodge/m...0C/2005_LX.pdf

 

Thanks bill

So if I'm looking at the diagram correctly, you're saying that if I jump pin 30 to pin 87 it should activate the compressor?

I went to the wreckers lastnight and picked up a couple of extra transducers. One of them came from a super clean car, the engine bay looked nearly brand new and everything was so clean so I have a good feeling that the transducer I grabbed from that car should be working, but it still doesn't activate the AC compressor.

I'll try and jump those pins on the relay and see if that does anything. Otherwise after this there isn't much to check. I can repalce the climate controls and if that fails to work then it has to down to the BCM or PCM which really concerns me. Any simple way to determine if either of those computers are bad somehow? Would there be any other symptoms?

 

Well that worked, Jumping pin 30 to 87 activated the compressor and the AC is working great.....though needs a slight top up now that I accidentally let out some gas.

So what does this mean now? Is climate control switch or BCM/PCM the only things that this could be now? Maybe the relay but it was swapped previously with the horn relay, and no matter how I swap them the horn still works. I'm going to double check the relay now with a meter, and then I guess figure out how to remove the climate controls so I can faff about with them a bit.

 

Is there anything I should be looking at with the climate controls? I removed them to look them over and I don't see any glaring problems like corrosion or cold lapped solder joints.

Other than this I'm not sure how I'd trace a broken wire or ground or something. I'm not sure where the wiring goes/comes from to be able to follow it all around.

 

Here's where I'm at now.

I measured the voltage across pin 85 and 86 of the relay and it was being weird. In one instance with the AC off I was getting about 9V, and with the AC on it was also about 9V. In another instance it was reading 13V but the relay won't activate.
voltage across pin 30 and 87 is 13V.

if I put the relay in the slot but leave it out enough to get my meter probes on the pins then I get no voltage reading across pin 85 and 86.

I'm also now met with a P0645 code (AC control circuit open) which was cleared and then stored again after I wasn't messing with anything.

Should I be looking at replacing the fuse box?

 

I pulled out plug C1 from the IPM and sure enough there is a Blue/Orange wire that was totally corroded and broken on the plug itself. So the IPM looks ok, but I guess I'm going to have to go to the wreckers again and cut off one of those plugs to solder in place of mine. It doesn't help that I broke the plug a little bit, and I may just grab another IPM for ****s and giggles anyway.

5 C13 20LB/OR A/C CLUTCH RELAY CONTROL

 

Good on you for staying after it. Hope this does the job.