2017 Ram 2500 4x4 AC Compressor issues

[Ryan Poulos]

I bought a 2017 Ram 2500 4x4 with. 6.4 hemi. 338,000 miles. Yes Im crazy but it was cheap and clean. It also had a dealer i stalled new long block 80,000 miles ago. But I bought the truck with the AC mot working. I live in Texas of course. Hot! Anyway, Clutch not engaging. I checked inside the fuse box and no 12v at the fuse. So I jumped the fuse side going to compressor clutch with 12v. It kicked on and worked. Then it worked after I put the fuse back in. Once I turned off the truck it showed no 12v at the AC clutch fuse once again. Has anyone seen this before and what was it? Thank you.

 

[jws123]

Have you checked the charge on the system to see if its low? Also wow over 300k on a 2017!! whoever had it musta drove ALOT hope ya got a good deal on it.

 

[Ryan Poulos]

I will get that later today. Dash switch goes on. No power at AC clutch fuse. What’s inbetween all that? Module? Relay?

 

[Ryan Poulos]

Oh and deal wasnt great great, but it does have a new long block with 80k on it and a new Jasper trans with 18,000 on it. I basically bought it for repair costs. Owner was a long hauler for some rich guys with show motorcycles.

 

[Tach_tech]

If the system is empty the compressor is not going to turn on. You need to put a set of manifold gauges on it at the very least to see what system pressure is.

 

[RAZ175]

Here's the wiring schematic.

 

[Ryan Poulos]

Thanks for the schematic.
So could be my Module Power Train Control eh? Or the pressure sensor not sensing Pressure so not telling the module to give the relay power to show power at the fuse. I see why earlier I need to check pressure first.

 

[Ryan Poulos]

Here's the wiring schematic.

View attachment 467311

 

[Ryan Poulos]

 

[Tach_tech]

If you only have 30psi resting pressure then that’s your problem. It’s low, get it evacuated and recharged with dye and go from there.

 

[Ryan Poulos]

So I heard a ‘hisssssss’ upfront. In this area. Could not feel it and sprayed soapy water but no bubbles. But its clearly leaking. So I guess an AC Condenser?

 

[jws123]

You could always put dye in the system and find the leak that way either way you will need to de charge evacuate re charge.

 

[Ryan Poulos]

Doing dye and a new condenser then vacuum test. Report back later.

 

[Ryan Poulos]

I just noticed these. Lube and use again or is this some oem part I need to get? I have green o rings but this washer and rubber inner edge looks like its all one part.

 

[Ryan Poulos]

Ok, new condenser in. Replaced both of those washer/o-ring things on the lines. Vacuumed down with a pump 15 min. Stayed at -20/30 (last pics) for 15 min.
recharged. And blowing at 50 degrees at the vents. But……did I overfill? I did one 12oz can and a 1/2 (or little more) of another. Trying to calculate 1.19lbs into ozs. Then I took an old charging can with the built in gauge on top and low side was where I showed the mark on the pic. Advice? Thanks everyone up to this point.

 

[Ryan Poulos]

Morning after update: I walked out this morning, did not start truck. Stuck the cheapy r134 can with gauge on low side for reading. See pic 1.
then I put good gauges on low and hi side. See pic 2. Lastly I started truck and thats pressures on the last pic. Am I overfilled or ok or ??? Thank you. Its still blowing 50 degrees at the vents.

 

[Tach_tech]

What are the high/low side readings with the engine running and A/C on? A/C systems are charged by weight so pressure readings only get you in the ballpark but you need the running pressures.

 

[Ryan Poulos]

About 40 low side and 20 high side. See pic. That’s running.

 

[Tach_tech]

With an ambient temp of around 21C/70F you should have low side pressure of 20-30psi and high side of 150-250psi. Your high side pressure is way low. Usually the only time high/low side pressures are equal is with the system not running or the compressor is not working. You could still be low as well. Your system capacity if it’s 134a is 1.19lbs/19oz.

 

[Ryan Poulos]

Thanks Tach_Tech.
Its 93 degrees here now. 48% humidity. Hot outside in Texas.
I used one full can of this with leak dye, and there is barely any left in this 2nd can. So almost 24ozs. So you think add more?
I let the truck run about 10 minutes. Checked with gauges. 50 on low, 50 on high.
Still blowing 50 at vents inside. Thank you.